Bore Rider Design

  • 842 Views
  • Last Post 6 days ago
Wm Cook posted this 2 weeks ago

Disclaimer; I've been shooting cast for 30 years but it's only been in the past two years that I focused on cast accuracy. In short I'm not smart enough to eat at the big people table when it comes to cast accuracy.  But to a degree I'm smart enough to listen to what they say and I do catch the occasional cuss word.

Two years ago I would have flunked the test for the definition of bore rider vs bearing surface.  Even today there may be a dispute about where bore riders design ends and bearing surface begins. But I hope we can start out with the expectation that bore riders must make contact with the lands.  between 20/1 and Linotype are a couple of variables that makes this a pointless to argue over.

Borerider accuracy: Pieces of the puzzle started to fall together when Covid hit and I started to spend a lot of time at the bench.  After a through weeding out of my gun safe I wound up with a new Savage 10F in .308.  That led to a second 10F in .308.  That was the start of the rabbit hole that had me hooked on the number of variables that must be controlled for accuracy. Not many will argue that cast accuracy is significantly tougher to achieve than jacketed accuracy.  And although I'm talking about bore riders I believe the majority of folks will agree that a properly fitted tapered design will be more accurate then a borerider. 

From Ken

i have always thought that bore riders are a good way to get down to about 1 moa, but full groove diameters necessary to get much under that

But I hope to have this thread focus on boreriders because it is user friendly for a number of shooters.  I think tapered design is better but there's a steep learning curve to understanding bullet to throat fit. 

A couple years ago the only competitive mold I had was a Lyman 311299.  This is a borerider design.  I may be way off base but it strikes me that the freebore design is a good middle of the road choice for a production rifle.  As long as the freebore can take .310 sized shanks you can get the gas check at the bottom of the neck and you should be reasonably accurate.  I believe the freebore design started with the Springfield four groove barrel way back when but I'm not a historian, ballistics expert or a machinist so others know a lot more than me. 

Unique to the .308 rig I'm working with is that the bore is oversized.  As best I can tell the bore on this barrel is ~ .3014.  I've tried to measure bore (tip to tip lands) every way come Sunday and its hard as heck for me to get an actual measurement on the bore.  I've tried measuring, using a small bore gauge, pound cast, chamber side bullet tap and even  reverse engineering guesstimate to see where the lands contact the nose (non bore riding bullet) but everything boiled down to an estimated ~ .3014 bore.

My two cavity Lyman 311299 drops similar bullets with a ~ .2985 to ~ .3004 nose.  The dimensions differ through the length of the nose but you get the picture.  With some support from someone on the forum I was hand fed the how to beagle a mold.  I haven't received my certification yet on Beagling but I've come far enough that I can compare nose to lands tolerance as an independent variable to cast accuracy.  

Results: Four five shot groups with a proven load were shot side by side. Lyman 311299 weighted to the .1 grain, #2 Lyman, 23.0g H4198 ~ 1760fps, Fed 210 primers, Can Bl lube, .335 bushing, sized .311.

  • ~ .2985 to .3004 nose diameter aggregate 2.285" MOA
  • ~ .3010 to .3014 nose diameter / aggregate of 1.453" MOA

I may be the last person on this forum to figure this out but I believe that bore rider tolerance is as critical to accuracy as olgive to lands is with jacketed bullets.  Where jacketed accuracy is found by starting on jam (.001 to .002 of sticking on a new barrel) and then backing off in increments of .002/,003; optimum bore rider accuracy may be found with nose to land tolerance of +/- .00025.  And although alloy (#2 Lyman vs Linotype) gives us a variable to work with, the alloy source is critical.  

OU812's design for sizing the nose seems like a big step towards to finding that sweet spot.  Beagling is another choice.  There is always the alloy and of course you have Tom who can cut anything you need for bore dimensions.  A custom mold and playing with the alloy can give you +/- .00025 to work with. Maybe the tolerance isn't as tight as I think.  Maybe .0005 impression of the lands on the nose is good enough.  Maybe .00075" is right.  Then on top of that throw in the typical BS / SS (Barrel Specific / Shooter Specific) factor and you have an interesting puzzle. 

Unique to my situation is that I have a tight freebore.  Instead of the SAAMI .310 I had ~ .3085 on each barrel.  My guess is that this bullet will never be competitive in the barrel I'm putting it through. That's why the bullets are seated down to the shoulder.  Thanks, Bill. 

Here is the difference between the .~.300 vs the ~.3014 nose on the bore of my rifle.

 

Attached Files

Order By: Standard | Newest | Votes
Spindrift posted this 2 weeks ago

Thank you for an interesting post!

Nice to hear your mould modification turned out well!

I have a .35 caliber bore- rider where I use another solution to the problem with an undersized nose. 

This is a CBE 360-300, the nose is about .349 in my (scrap) alloy. First, I size the nose in the NOE bushing sizer, using a .349 bushing. This doesn’t really size the nose, more clean up the mould seams. Then I powder coat the bullet, which adds about 0,002in size. Then, I run it into a .351 bushing that even out the high spots that might be there. These bullets shoot very well with 45 grs Vihtavuori N150, actually one of my most consistently accurate load.

 

The NOE bushing sizer is an excellent, clever tool. The nose sizing function, though, has clear limitations. If you try to size down 0,001in, you’ll cut a ring of lead that’ll end up by the front driving band. It is a marginal tool for minimal modifications.

Attached Files

John Alexander posted this 2 weeks ago

Wm Cook,

Very interesting statement of some of the factors to be dealt with in fitting a bullet to a throat. I hope it leads to productive additional discussion.

As you have observed threads on a forum tend to go in all directions often getting off on to a completely different issue. I am not so green that I think this can be entirely prevented, or in some cases or that it is always a bad thing, but it, maybe, can be partially avoided with a a good definition of some key terms.  I believe that most on this forum understands what a bore riding bullet is, but I think your definition of the two approaches below would help keep us on the same page.

Properly fitted tapered design

Freebore design 

John

 

Attached Files

OU812 posted this 2 weeks ago

Squeezing the bullet to a more perfect round shape and then fitting to throat can be rewarding. You can make a simple die using aluminum rod. Drill then ream the aluminum to desired size. Hardest part is machining a nose punch to fit bullet tip perfectly. You can sqeeze bullet by striking with rubber dead blow hammer, but i use a press. It would be nice if NOE moulds would sell such a die since they have CNC 

Attached Files

OU812 posted this 2 weeks ago

The trick to reaming is you must stop the lathe when extracting reamer because it is still cutting.

Attached Files

John Carlson posted this 2 weeks ago

I also use the NOE nose sizing dies.  I found that it helps significantly to touch the entry with a tapered grindstone then polish the die with 2000 wet-or-dry with oil.  Finished product is about .0003 oversize. Lead slicing is not a problem when reducing diameter up to .002 with lube sizing 311299/314299 bullets.  I use the same treatment on Lee push through sizing dies and find no need for lube.

I have not yet found the sweet spot and generally cannot identify a measurable and repeatable improvement in accuracy with nose-sized bullets vs the same bullets as cast.  Doesn't mean I won't keep trying and I will certainly be following this discussion.

Holding public office should be viewed as an obligation to serve, not an opportunity to rule.

Attached Files

  • Liked by
  • Spindrift
Wm Cook posted this 2 weeks ago

I believe that most on this forum understands what a bore riding bullet is, but I think your definition of the two approaches below would help keep us on the same page.

Properly fitted tapered design

Freebore design

In the OP I asked about bore riders. It's simple and doesn't have the controversy of ball fitting.  I was hoping to stick with bore riders on this thread.  I'll start another thread about tapered design because that seems to be an area where a lot of progress can be made.  And that's an area where there is a lot of controversy.  Impassioned myths will be intermingled with statically valid results.  And its also one of the remaining pockets of "tricks" that can give a shooter a competitive edge.  So in hopes of keeping this thread on track I was only speaking of true bore riders.

Cast bullet design will continue to evolve as accuracy is pursued.  Perhaps the bore rider design is not as susceptible  to change?  I'm not a historian but as I understand it the Springfield 4 groove barrel was one of the first to benefit from bore riders.  I have not researched this further.  Maybe others on the site can give us a better of the historical place bore riders paced in cast bullets.

To me it seems that there are two obvious dimensions to fiddle with on a bore rider.  The shank diameter and the nose diameter.  Using common numbers like .310 for the shank and .300 for the bore fitting nose would be common in a 30 caliber mold.  A simple definition would be that a bore rider bullet's nose is the same diameter as the rifle bore.  Full load bearing only occurs on the driving bands.  The nose is controlled, leaning against, or bouncing off the lands dependent upon the tolerance between the bore and the diameter of the nose. 

I am politically dodging the variable of a bore rider driving band seated into the lands.  Not that that's a bad idea.  The Lyman 311299 looks more like a 30-06 bullet than a .308 because of its bullet base to front driving band. But if the driving band will pass through your freebore on a .308 you could put most of  front driving band >.100" into the freebore and have the bullet base in the bottom of the neck and nearly touching the lands with a production rifle throat.  SAAMI specification is .310.  My freebore is .3084.  A common .30 cal bullet size is .310 so there may be a conflict on some chambers. 

What I'm trying to learn is if anyone is using the nose diameter as an independent variable to tune for accuracy.  OU812 is an emphatic yes. His method of pressing the nose into a round uniform shape and diameter will work but it will be hard for the average reloader to replicate.   The NOE die is another choice.  But if I were tuning a load by varying the tolerance of the nose to the lands I would have to be able to readily adjust it to shoot a simple 2 x 2 design method.  Linotype vs #2 Lyman may give me that.  I don't have enough experience to say that I will truly gain .0005 with Linotype.  I'll know about that in about 4 weeks.  

I know I'm always making apologies like "gee if only I had...." but I am a born tinkerer and get my jollies manipulating variables to see if there are statically solid results.  Its easy for me to dream about a bore rider design three cavity aluminum mold from Accurate.  One cavity each .299, .300 and .301.  Then cast with both #2 Lyman and then with Linotype.  Combine those 6 variables with dependent variables (powder, charge, case, weight, COAL etc) and you could wring out the value of +/- .0005 on a bore rider nose. That would give you a 6x study that would be statistically valid.  A tapered design may still be more accurate but for ease of use the bore rider bullet is attractive to a lot of people.

Final note on bore riders: Accuracy will try to cut any nose diameter you want.  His tolerance for dimensions on bore rider nose is +.000 and - .001/.002.  He tries to be within tenths of a thousands on the dimensions requested but results are too convoluted when you add in the alloy that's used and user specific casting methods.  Note: he does ask for the alloy you use so compensation is fudged in to reach the dimensions you need.

The following is the drawing for Tom's 31-175 bore rider.  It is a good example of how a bore rider looks.  I have his original drawing that has all of the dimensions on it on the right. 

Just cause I'm a geek I would like to point out the .245" where the top driving band starts and .355 where the top driving band ends.  This bullet makes it a good fit for the .308 Winchester. which has a neck length of .303.

Attached Files

OU812 posted this 2 weeks ago

John Ardito was an engineer, machinist, gunsmith. So he had done lots of experimenting. He could machine a chamber/throat to any of his ideas. I bet he had lots of barrels and reamers laying around in his shop.

I wonder if ever experimented compressing the bullet to align the nose.

Attached Files

Wm Cook posted this 2 weeks ago

OU I will never match your knowledge of what can be done with reamers.  I have to reverse engineer to visualize what the freebore, leade looks like. 

But the bore rider is such a simple affair that getting the nose to the right dimension is doable.  You're compression method would work if you knew what diameter you wanted.  You could make a stepped improvement with one bushing but trial and error would be needed to get the tune right.  .If I were talented enough and if I could operate my lil Jet lathe in my shop I could probably turn out several bushings and do a side by side study myself.

Wouldn't it be funny if the next step in cast accuracy was a high velocity, hard, heavy, long bore rider compressed to uniformity and sized to get the most out of the bore/nose fit.

IMHO iIf the relationship between diameter of the nose and the bore is as important as I believe, tI would guess that there may be a  50% improvement (not just a .5 MOA improvement) in group size.  The definition of group size in this case is the aggregate of four 5 shot groups.  All of the foundations for accuracy (casting, handloading and bench discipline) would naturally need to be in place,

Then again, maybe cast accuracy buffs have already passed on the bore rider and are focused on finding the right combination to seat the bullet into the throat with a tapered design.  Take care, Bill.

Attached Files

OU812 posted this 2 weeks ago

Your posted picture of the as cast bullet will deliver standard boring accuracy. You must try something different. What size bullet do you think you need. Maybe I can machine a die to fit your gun and make you some more perfect bullets from my mould. Will have to dust off the mini lathe...not easy.

What is the length of your freebore, testing has shown longer freebores work best. My old Remington had the NATO chamber with long .190 freebore length...gun shot really good until i ruined it by lengthening freebore too long.

Attached Files

John Alexander posted this 2 weeks ago

Wm Cook,

Thank you for taking the time to explain what you have in mind and how you intend to do it. I am glad that you are confining your plans to the bore rider type bullet. I think it has proven its superiority in factory rifles by its popularity in our military matches and in Production and HNR classes.

I also think it is seldom tried in the full race guns in Heavy, UNR, and UNP. If everybody is using the Ardito approach then that approach will win the match. I wonder what the full potential of the bore rider is if given a good try with the high priced guns?  Your proposed experiments should get us a little closer to the answer. 

A few random bits from 40 years of shooting bore riding bullets that may or may not be useful: Hard bullets will not seat with more than the light land marks. Soft bullets seem to shoot better with heavy engraving, but not so much that you don't get firm contact in the throat by the first driving band. Rounding of the bullet edges and pretty big wrinkles in the bullet seem to have no effect on accuracy down to about 0.8 MOA and maybe beyond.

Good luck with your experiments.  We will look forward to your results.

John

Attached Files

  • Liked by
  • Maven
  • Spindrift
OU812 posted this 2 weeks ago

John, Have you considered rebarreling your 6mm ppc to shoot 30 BR. You could turn down the larger case rim of 30 BR to fit your smaller bolt face. This way you would not have to buy larger bolt face. Then experiment with bore riders.

Attached Files

Tom Acheson posted this 2 weeks ago

 

There’s a lot of interesting information being exchanged here!

 

Those of you who shoot in the CBA matches have seen the note on the Tech Data sheet asking for the bullet size diameter and the NOSE diameter. I’ve never included the nose diameter on the many tech sheets I’ve filled out. After reading this post, some people who read the match results might find the nose diameter an important data point. From my uninformed perspective I concluded long ago that if the bullet is being engraved by the rifling, what does the nose diameter matter? Dumb question time….are there bullets whose surface is 100% bore riding and no engraving takes place? Probably not, otherwise why is rifling present? If the bore ride area is short, how much does guidance does it impart on the bullet? I assume (probably incorrectly) that the role of the bore ride area is to help guide the bullet and help keep it centered in the bore.

 

I’ve used a bump die on several of my previous rounds. The stem in the die that provides the effort to eject the bumped bullet, has a conical recess machined in the end of it. So that the recess does not damage the bullet’s nose, a soft lead “slug” or molten lead is inserted into the recess. Then as bullets are bumped, the soft lead deforms, taking on the shape of the bullet’s nose. Over time, this soft lead “nose forming material” needs to be removed and replaced.

 

The bump die can be adjusted to position the start of the tapered area on a bullet. On a single lube groove bullet, this location has been on the middle of the driving band above the lube groove. The taper on the bumped bullet matches the “taper” in the chamber (not a factory rifle) so the “fit” is a cone in a matching cone. I guess this is one form of “bullet fit”.

 

FWIW

 

Tom

Attached Files

MP1886 posted this 2 weeks ago

John, Have you considered rebarreling your 6mm ppc to shoot 30 BR. You could turn down the larger case rim of 30 BR to fit your smaller bolt face. This way you would not have to buy larger bolt face. Then experiment with bore riders.
Personally myself I'd keep the 6mm PPC, it's a great little cartridge.  "There are bore riders that will work in it. 
Not your 6mmPPC,  but I built a match AR15 in 6x45 and shoot cast from it exclusively.  It's deadly accurate. It's gets to be quite boring. I shoot a bullet using a mold from Mihec. 

Attached Files

RicinYakima posted this 2 weeks ago

Download PDF of Secrets of the Houston Warehouse By Dave Scott Precision Shooting Magazine Special Edition 1 1993
Download Full Article – Secrets of the Houston Warehouse By Dave Scott
Originally Published in Precision Shooting Magazine Special Edition #1 1993

29 years old now, but jacketed BR shooters have not beaten these in outdoor matches. 

FWIW, Ric

Attached Files

  • Liked by
  • John Alexander
OU812 posted this 2 weeks ago

John, I agree with your statement, sometimes I speak before I think. Although for me the smaller 6mm would be harder to machine dies for. Lots more bullet choices in larger calibers. Accurate does not offer a 6mm option...I think. NOE is a good option.

Attached Files

MP1886 posted this 2 weeks ago

John, I agree with your statement, sometimes I speak before I think. Although for me the smaller 6mm would be harder to machine dies for. Lots more bullet choices in larger calibers. Accurate does not offer a 6mm option...I think. NOE is a good option.
Saeco and Mihec do.

Attached Files

OU812 posted this 2 weeks ago

Tom A.,
I have seen your legendary groups in the Lyman reloading manual. You do know what your talking about.

Attached Files

Tom Acheson posted this 2 weeks ago

OU8,

Wish I could take credit for the groups in the photo. That is my rifle. The targets are examples that I collected over a couple of summers from CBA Postal match entries. I toss out targets that I scored but sorted those in the photo to be from shooters using the noted Lyman bullet and powder.

As a Postal scorer, I get to see a lot of targets. The event I score is called a “season” event, meaning you shoot and send in targets for scoring in May, June, July and August. Most of the CBA rifle categories are available. Heavy and Unrestricted don’t always have the smallest groups, as one might anticipate.

Using that photo at the start of the chapter was an attempt to get non CBer’s attention and maybe read the chapter.

Experienced CBA match shooters would not be surprised by the groups, especially if you have attended the CBA National Tournament.

Tom

Attached Files

John Alexander posted this 2 weeks ago

I have considered rebarreling my 6PPC to 30 BR and other calibers as well. If it weren't for the slow twist of my present barrels I would try to get a suitable similar to the 22 bullets I am using. But the slow twist would require a short CB and you don't see many short CBs in the winners column for good reasons.  Long bullets are easier to achieve good alignment upon seating and also provide higher BCs,

The other reason is I enjoy shooting practical hunting rifles in competition.

OU812 is right there are a lot more mold choices. Most mold makers won't make 22 molds and won't consider 22 spitzer molds.  Fortunately we have NOE.

John 

Attached Files

  • Liked by
  • RicinYakima
John Alexander posted this 2 weeks ago

Tom asks:

"If the bore ride area is short, how much does guidance does it impart on the bullet? I assume (probably incorrectly) that the role of the bore ride area is to help guide the bullet and help keep it centered in the bore.

===

The answer to your question is -- less than it needs to be. I believe your assumption is correct about the role of the nose.  That is why a good bore riding bullet should be mostly snout. The longer the better, in my opinion. 

John

Attached Files

  • Liked by
  • RicinYakima
Wm Cook posted this 2 weeks ago

What size bullet do you think you need. Maybe I can machine a die to fit your gun and make you some more perfect bullets from my mould. Will have to dust off the mini lathe...not easy.

What is the length of your freebore, testing has shown longer freebores work best. My old Remington had the NATO chamber with long .190 freebore length...gun shot really good until i ruined it by lengthening freebore too long.

OU the factory bore length was .120" +/- .010.  I took a diversion and had it moved out to .220.  A mold came in from Accurate yesterday and I should know how well it fits the throat by mid week.

I concluded long ago that if the bullet is being engraved by the rifling, what does the nose diameter matter? Dumb question time….are there bullets whose surface is 100% bore riding and no engraving takes place? Probably not, otherwise why is rifling present? If the bore ride area is short, how much does guidance does it impart on the bullet?

Tom I concede the point.  If the bullet is rattling down the barrel that would be one thing.  if the lands control the travel of the bullet down the bore growing the diameter will probably only show fractional accuracy improvements.  As I was working up the nose diameter by beagling I could see the differences in contact and accuracy between the lands and the nose.  No contact at .3000, faint at .3005, enough contact you could feel the imprint on the nose at .3015 until it was a no go at .3020. 

That made me think about bore riding as the nose leaning on the lands with the only shank of the bullet (south of the front driving band) making full bearing surface (groove diameter).  Just a hypothesis here but I think that the greater the contact (impression of the lands on the nose) the greater the control and accuracy will improve.  Are there easier paths to accuracy gains?  Yes.  I was working with a bore rider and started day dreaming.  

I don't think many would argue (but you never can tell) but in principle the greater the bearing surface the better the chance for accuracy.  And I think that if the delta between the nose diameter and the tips of the lands (bore diameter can effectively control the bullet and accuracy.  I know I'm chasing something that's not important to 99.9% of us. 

With the as cast nose diameter of .2988 / .3001 I shot pretty big groups. With a beagled diameter of .3011 / .3015 (oval shaped due to beagling) the groups shrank. So what would accuracy be like if I had a true .3016 the full length of the nose. Playing with alloy's can give a bit of a fluff factor. But I was just wondering.

I know.  Just shut your trap and move on to a different bullet design. There are easier, cheaper, more productive ways to pursue cast accuracy.  I was just curious if anyone tried to tune for accuracy by futzing with the diameter of a bore rider's nose.  

Thanks, Bill.

 

Attached Files

OU812 posted this 2 weeks ago

Purchase the Lee collet neck sizer and adjust neck tension to be just enough to chamber bullet. Too much neck tension will not help align bullet when chambered.

I have been shooting cast for about 5 years...mostly .223 Remington. The bullet always shot better when squeezed larger and more round to fit throat/bore.

I had planned on buying a factory chambered 308 to shoot my bullet in, but never did. Wanting another Remington with the bigger NATO throat...Police version probably.

Attached Files

  • Liked by
  • John Alexander
DanLH posted this 2 weeks ago

I can answer the question about John Ardito bumping bullets. He once made up a 32 cal barrel and didn't have a 32 mold so he bumped up 30 cal cast bullets for his 32 barrel and I believe it shot very well.

Attached Files

Tom Acheson posted this 2 weeks ago

John A.


I believe your assumption is correct about the role of the nose.  That is why a good bore riding bullet should be mostly snout. The longer the better, in my opinion. 

By snout (stout?) you mean the length of the bore riding portion should be short and by the length, the longer the whole bullet the better?

Tom

Attached Files

45 2.1 posted this 2 weeks ago

That made me think about bore riding as the nose leaning on the lands with the only shank of the bullet (south of the front driving band) making full bearing surface (groove diameter). 

Once a rifle is shot much, the lands and throat area are no longer cylindrical/parallel. They have a curved taper that moves forward when more wear happens at basically the same shape. A bore rider/parallel nose will only contact in one place as the base is free to tilt the bullet (upon ignition) some (assuming the neck/chamber clearance is more than 0.001"). This is the reason accuracy is problematical above certain velocities.

Attached Files

MP1886 posted this 2 weeks ago

That made me think about bore riding as the nose leaning on the lands with the only shank of the bullet (south of the front driving band) making full bearing surface (groove diameter). 

Once a rifle is shot much, the lands and throat area are no longer cylindrical/parallel. They have a curved taper that moves forward when more wear happens at basically the same shape. A bore rider/parallel nose will only contact in one place as the base is free to tilt the bullet (upon ignition) some (assuming the neck/chamber clearance is more than 0.001"). This is the reason accuracy is problematical above certain velocities.

 

....and that base free to tilt sir is why we know engraving the nose of a bullet is NOT always a cure all!

Attached Files

Wm Cook posted this 2 weeks ago

Once a rifle is shot much, the lands and throat area are no longer cylindrical/parallel. They have a curved taper that moves forward when more wear happens at basically the same shape. A bore rider/parallel nose will only contact in one place as the base is free to tilt the bullet (upon ignition) some (assuming the neck/chamber clearance is more than 0.001"). This is the reason accuracy is problematical above certain velocities

Re 45 2.1: As a disclaimer; I'm not picking a fight.  Just trying to learn.

the base is free to tilt the bullet (upon ignition) some (assuming the neck/chamber clearance is more than 0.001")

"The base is free to tilt the bullet (upon ignition) some (assuming the neck/chamber clearance is more than .001". Sounds like common sense,but if the bullet is sized .310 and if the chamber is to SAAMI spec (.310 x .090" free bore) wouldn't the shank of the bullet be controlled in the free bore immediately upon ignition?  And in conjunction with a "long snouted" properly fitted bore rider bullet tipping would be prevented? 

I'm just struggling with shank end initiating the onset of tipping.  No offense meant by questioning this.  I have a lot to learn. 

Thanks, Bill.

 

Attached Files

OU812 posted this 2 weeks ago

Uneven throat wear is caused by higher powered jacketed loads. If a new barrel shoots a properly fitted cast bullet only you will not have that problem anytime soon.

Attached Files

John Alexander posted this 2 weeks ago

Tom wrote: "By snout (stout?) you mean the length of the bore riding portion should be short and by the length, the longer the whole bullet the better?"

My apologies to all.  I was just trying to be a smart ass. I should have used the term nose. I grew up on a farm with hogs and snout and nose were interchangeable. Not everybody was so lucky.

John

 

Attached Files

Tom Acheson posted this 2 weeks ago

It’s OK John. I didn’t grow up on a farm but visited relatives on farms in central ND during the summer. They even let me drive a tractor and pull the rope on a dump rake to make windrows of hay. One lasting memory….they were not afraid to eat! Good thing I was young and burned-up the calories, couldn’t eat like that today. Would have to have the cardiologist on speed dial.


Man, that Houston warehouse article is a bit long but very interesting. Sure do wish some CB shooters had the chance to try it out. Us with our wind flags, concern for wind bucking qualities and slow moving, heavy bullets. Would be a great learning experience.

Tom

 

Attached Files

Ken Campbell Iowa posted this 2 weeks ago

just a note:  it isn't the jacket ( or lead ) that wears the throat ... it is the powder ...   

great thread.  keep it up.

ken

Attached Files

  • Liked by
  • John Alexander
Wm Cook posted this 2 weeks ago

“I grew up on a farm with hogs and snout and nose were interchangeable. Not everybody was so lucky.”

Born and raised on a farm. We were dirt poor but learned manners, responsibility and work ethics before we hit first grade. Grew up thinking that a 22 rimfire was as natural a tool as a pitch fork, shovel or hoe.

Houston warehouse. Our club now has the building up for our 50 yard indoor range. We should be live in 2023. It’ll be invaluable in wringing out scores of cast variables.

But we all know, you can’t equate indoor conditions with the reality of match day conditions.

But yes, the thought of having a 24/7 365 day environmentally controlled range makes me drool.

Thanks, Bill.

Attached Files

Wm Cook posted this 2 weeks ago

“ just a note: it isn't the jacket ( or lead ) that wears the throat ... it is the powder ... ”

+1 on Ken’s comment on powder. The smaller the bore, the higher the velocity the quicker the bore’ll disappear. IMHO.

Had a 17 HeeBee that ran north of 3800fps and I had the bore disappear with just three days of shooting prairie dogs way back when.

But it was in a Ruger #1 that was so sweet to shoot.

Got old and I’m perfectly content with 200 grain cast bullets running 1750 fps and with it a barrel life that can’t be beat.

Thanks, Bill

Attached Files

Tom Acheson posted this 2 weeks ago

I think Ken is correct. My first sod poodle gun was a Winch Model 70 with a maple thumbhole stock, Unertl scope and chambered in 220 Swift. Yes, a rimmed bottleneck case. Every time the brass needed to be reloaded, the cartridge OAL grew, sometimes quite a bit. These were 50-grain jacketed bullets @ close to 3400-3500 fps. Forgot the powder #. Eventually, to get the bullet to lightly contact the lands, the bullet had to be out of the case!

Tom

Attached Files

MP1886 posted this 2 weeks ago

Uneven throat wear is caused by higher powered jacketed loads. If a new barrel shoots a properly fitted cast bullet only you will not have that problem anytime soon.
Yeah, well try shooting that cast bullet cast of Linotype at HV and  tell me the problem won't occur anytime soon.

Attached Files

  • Liked by
  • RicinYakima
MP1886 posted this 2 weeks ago

Once a rifle is shot much, the lands and throat area are no longer cylindrical/parallel. They have a curved taper that moves forward when more wear happens at basically the same shape. A bore rider/parallel nose will only contact in one place as the base is free to tilt the bullet (upon ignition) some (assuming the neck/chamber clearance is more than 0.001"). This is the reason accuracy is problematical above certain velocities

Re 45 2.1: As a disclaimer; I'm not picking a fight.  Just trying to learn.

the base is free to tilt the bullet (upon ignition) some (assuming the neck/chamber clearance is more than 0.001")

"The base is free to tilt the bullet (upon ignition) some (assuming the neck/chamber clearance is more than .001". Sounds like common sense,but if the bullet is sized .310 and if the chamber is to SAAMI spec (.310 x .090" free bore) wouldn't the shank of the bullet be controlled in the free bore immediately upon ignition?  And in conjunction with a "long snouted" properly fitted bore rider bullet tipping would be prevented? 

I'm just struggling with shank end initiating the onset of tipping.  No offense meant by questioning this.  I have a lot to learn. 

Thanks, Bill.

 

Bill,  I'm not picking a fight either, but with many members  pull the "racist card" by saying they aren't looking for a fight. I'm not sticking up of 45 2.1, he can very well stand alone, but I didn't see what he said as picking a fight.  I saw it as something very logical and actually trying to help, as I was with my comment after his.   

 

Attached Files

Wm Cook posted this 2 weeks ago

Totally agree with MP.

Just wanted to soften my comment back to 45 2.1 about his message so it wasn’t misinterpreted as a slam on what he said.

From your response I would say I failed miserably.

Thanks, Bill.

Attached Files

John Alexander posted this 2 weeks ago

45 2.1 wrote: Once a rifle is shot much, the lands and throat area are no longer cylindrical/parallel. They have a curved taper that moves forward when more wear happens at basically the same shape. A bore rider/parallel nose will only contact in one place as the base is free to tilt the bullet (upon ignition) some (assuming the neck/chamber clearance is more than 0.001"). This is the reason accuracy is problematical above certain velocities.

=====

45 2.1 is right, of course the bore near the breech will erode and no longer be cylindrical. Thus, the portion of the nose of a bore riding bullet near the driving bands may no longer engrave, but only when the depth of erosion becomes greater than the depth of the engraving. Even after this happens and some of the rear of the nose doesn't touch the bore it doesn't make much, if any, difference because the front half of the nose is much more important for aligning the seated bullet than the rear half (longer lever arm and it enters the bore first) and the rear half probably does little anyway.

Another reason not to to get too wrought up about this theoretical problem is that with moderate CB loads erosion occurs slowly. My match rifle has 15K loads though the bore, 90% CBs, and my best bore riding bullet now only engraves on the forward half of the nose. My log book and recent matches tell me that the rifle is shooting at least as well as when new.

It is yet to be proven (since there has never been a serious effort to find out) that bore riding bullets are no good for high velocity. If they fail as high speed CBs this may be important to hunters, but of little interest to match shooters or shooters striving for accuracy for the heck of it. The shooters in CBA's PBB class have shown that muzzle velocities of 1450 fps shoot aggregates just as small as those of the shooters in heavy class shooting at 2100 fps.

John

 

 

Attached Files

MP1886 posted this 2 weeks ago

Totally agree with MP. Just wanted to soften my comment back to 45 2.1 about his message so it wasn’t misinterpreted as a slam on what he said. From your response I would say I failed miserably. Thanks, Bill.
Bill,
If you learned something from your tests, even you may think they failed, then I don't see them as a failure, I see them as having taught you something. Sometimes Bill I'll even shoot some loads that I made purposely bad to  see what I can learn from them.

Attached Files

45 2.1 posted this 2 weeks ago

I'm just struggling with shank end initiating the onset of tipping.  No offense meant by questioning this.  I have a lot to learn. 

Thanks, Bill.

No offense taken Bill. If it does tip and not obturate, then it starts crooked. If it's started out of line, exactly what is there to straighten it to the bore? Bore ride bullets will shoot well as long as they're not pushed hard and they actually engrave the nose and the driving bands fit properly. However, a tapered bullet of proper dimensions has something to straighten it up as it gets into the throat. I've found accuracy or lack of it is already decided before the bullet leaves the case neck. Other things enter into this, but no one has ever addressed them.

Attached Files

Tom Acheson posted this 2 weeks ago

This bore riding thing has my interest. I’m assembling a new CBA gun (an XP-100, a bolt action single shot “hand rifle&rdquo and find myself considering the NOE gizmos that permit you to alter the diameter of the nose.

I realize that I’m asking for trouble with the following question….

Is there anyone involved with this thread that can offer any advice as to what is the desired relationship between the measured bore (land ID) and OD of the bore riding portion of the bullet nose?

Thanks!

Tom

 

Attached Files

OU812 posted this 2 weeks ago

PTG sells the reamer pilots as a ten piece kit. You can easily figure what your bore measures. Trail and error on bullet shape and sizes is up to you. I have never had much luck using the NOE bore ride sizers. I believe squeezing a smaller diameter bullet larger and aligning the nose in same step works much better. This may require sanding die larger to fine tune.

Attached Files

OU812 posted this 2 weeks ago

Tom A.,

What caliber are you going with.

Attached Files

OU812 posted this 2 weeks ago

Although I have used the NOE bore ride sizer to reduce size before bumping.

Attached Files

Ken Campbell Iowa posted this 2 weeks ago

on a lighter note...  kinda relevent to fresh throats .. weakly relevant ...

John A should ... upon wearing out his magic 223  ...  or being outlawed at the CBA Nats ...  rechamber that same barrel to  22-250.

reason being that JoeB spent many hours and bullets ... an excellent shooter with excellent technique and excellent equipment ...  showing that 22-250 chambers are more accurate than 223 chambers.  yep, grit your teeth but hard to ignore ...

just think how good that prize winner Tikka would be in an accurate cartridge !! ...

enough for now, i had my fun.  ken

 

 

Attached Files

  • Liked by
  • John Carlson
Wm Cook posted this 2 weeks ago

John A should ... upon wearing out his magic 223  ...  or being outlawed at the CBA Nats ...  rechamber that same barrel to  22-250.

Ken, I heard rumors that at this years annual board meeting the CBA has an agenda item to discuss the creation of of a "Youth Hunter Class" for all .22's to shoot in. Heard that their doing that because the .223 Rem is kinda known for being so-so on accuracy.  Some felt it wasn't fair to have .223's compete against real actual manly bona fide accurate cartridges.  Just kidding.  Really I am kidding.  I meant no disrespect.   Again, kidding.  Really and truly kidding. Not picking a fight here MP.

The real questions is how much insurance he has on that D Mos mold?

.22-250?  Maybe.  Since he would be shooting out of class I would see if there's enough life in the barrel to have it re-chambered for .222 Rem.  I always had a soft spot in my heart for the .222.  But since some rifles fall into that "old home week" classification he'd probably scrounge up a new factory .223 barrel and just keep going.  Thanks, Bill.

Attached Files

Paul Pollard posted this 2 weeks ago

Tom Acheson asked, "Is there anyone involved with this thread that can offer any advice as to what is the desired relationship between the measured bore (land ID) and OD of the bore riding portion of the bullet nose?"

I did a test of nose sizes in 2017 for my 6mm. The Mountain Molds bullet was a copy of the Eagan design, except the nose came to a point. The Eagan was a truncated cone. The other dimensions were the same.

I made bump dies with 11 different nose reamers. The noses ranged from .2355 and ended at .2395. The rear portion of the die sized the base band at .245. The front band was tapered at 3 degree included angle to fit the throat tapered section. The rifle had a well-worn throat, so I thought a larger nose was needed. It turned out that the nose of .2367 was the best grouping. It felt loose in the bore at the muzzle. There was not really any engraving.

 

Attached Files

  • Liked by
  • Spindrift
Ken Campbell Iowa posted this 2 weeks ago

paul pollard ..  " loose nose shot best " 

*******

are you saying cast bullets can't read ? ...

Attached Files

John Alexander posted this 2 weeks ago

Tom: My experience is that with linotype any engraving but the lightest may cause trouble chambering the bullet and run the risk of pushing some of them back somewhat in the case.  But some engraving shot better than none. With soft (25:1) bullets anything from light to 0.002" may shoot. But mine seem to like more engraving rather then less. This with a beagled bullet that is no longer round and usually shows only 4 of six land marks.  This is a bullet with a nose 66% of length and a uniform diameter bore ride section that is of 40% of of total length --if that makes any difference.

This is a guess but I wouldn't be suprised if a very hard bullet might shoot well with the bullet almost big enough to engrave. 

Attached Files

Tom Acheson posted this 2 weeks ago

OU8,

The cartridge will be a 22 BR. Cases are re-formed 6.5 BR. The starting mold will be an NOE 227-79-SP-B5

Lilja barrel, 1:8 twist 3-groove.

Tom

Attached Files

Tom Acheson posted this 2 weeks ago

John,

I’ve been all over the map on alloy hardness. On the soft end for a Remington Rolling Block in .38-55 with 27:1. The other end was a 30 PPC using 50/50 Lino /Mono @ about 32 bhn (I think). For my Sharps .40-70 SS (40 cal. 2 1/2) 15-16:1 seems to be working (today).

For this new project I need to start somewhere. I have quite a bit of pure lead, wheel weights and tin.

Tom

Attached Files

Squid Boy posted this 2 weeks ago

I am still pretty new at this but figured that more nose ride the better and the bullet I designed could have been a bit longer but the throat is short in my Stevens 44 in 32-40 and almost all of the nose is the barrel when it is loaded. The engraving is only half a thousandth per side so it goes in pretty easy. This is the second (string 2) target I shot with it at 100 yards after getting it on the bull. 20-1 alloy and the load data is on the target. I need to get back and shoot this more. Squid Boy

 

Accurate 32-172D

 

 

Target String 2 - 10 shots - 100 yards

"Squid Pro Quo"

Attached Files

OU812 posted this 2 weeks ago

I've also had real good results using the softer 20/1 alloy in 233 Remington at lower velocities (Tite Group powder) . Also had good results using linotype at higher velocities (4198 powder, Reloader 7) Lots of testing and lots of rounds fired.

Reloader 7 works good in 308. Never tried Tite Group in 308, but I am sure it will work at lower velocities. Please try it with 20/1 alloy.

Attached Files

OU812 posted this 1 weeks ago

This next question may require a topic on its on. What is the perfect free bore length and diameter when using 30 caliber bore ride style cast bullets. A freebore that will also shoot jacketed well also.

I think a .310 diameter by .200 length would be perfect for most. Much like the 308 NATO. Isn't it legal to cut freebore longer if need be?

Attached Files

John Alexander posted this 1 weeks ago

If by legal you mean eligible for CBA competition the answer is it is in all classes except Hunting Rifle Class.  Can't do anything to rifles in HR except adjust the factory trigger and rebed. This is to keep cost of equipment to compete in HR to a bare minimum.

John

Attached Files

Ken Campbell Iowa posted this 1 weeks ago

my 2 cents on freebore ... it should be less than 1/2 thou bigger than groove diameter ... and very little longer than the protruding groove dia of your bullet seated out as far as you retain the bullet.

this for a match chamber.  heh, another $300 for PTG ...

ken

Attached Files

OU812 posted this 1 weeks ago

Seated bullet case neck clearance in chamber should be tight also.

Attached Files

Squid Boy posted this 1 weeks ago

The bullet/case neck clearance on this set-up is about two thousandths. Squid Boy

"Squid Pro Quo"

Attached Files

Tom Acheson posted this 1 weeks ago

This might be off base but....about the tightest ckearance between the OD of a loaded round and the ID of the chaber's neck area is often expressed as 1/2 thou per side. There must always be some room for the brass to expand during ignition. You need to mic (not caliper) the OD of the loaded round and know for certain the ID of the chamber neck. When that clearance is reduced, you start to get into neck turning, etc. 

This sees the advantage of necks that are too thick. You get to customize the bras to fit the chamber. But...if you change the OD of the sized cast bullet, all dimensions need to be re-evaluated. Sizing smaller isn't a bad thing but be real careful if you increase the size of the cast bullet.

Tom

 

Attached Files

RicinYakima posted this 1 weeks ago

Question. Not being funny, but why does the neck have to expand? We put the bullet in there when the neck ID is less the the OD of the bullet. So why doesn't it just slide out when the round is fired?

Attached Files

  • Liked by
  • John Alexander
Ken Campbell Iowa posted this 1 weeks ago

Ric .. probably the biggest reason for neck expansion is ::  to seal the front of the chamber ...  

next is perhaps that tolerances would eventually cause a dangerous tight pinch if the goal was zero clearance in the chamber neck ...

but i wouldn't worry much if loaded with lead and to our usual medium pressures worked up. 

ken

 

Attached Files

  • Liked by
  • John Alexander
MP1886 posted this 1 weeks ago

I guess I see this different then most.  First I have to ask about straight wall cases. They have a neck such as a bottleneck.  LOL just being silly guys.  Okay, neck expansion: simple reason is that the whole case swells from the gas pressure inside. Think obturation.  The gas also gets up to the neck. I don't think "they" back in the early days of cartridge cases really planned for necks to expand and seal, it just happened. Y'all making too much out of it.

Attached Files

Squid Boy posted this 6 days ago

I have a couple using custom bullets that measure a half thousandth clearance per side. I also had one that needed a bullet that was .470" on the base to do it and going into a .462" groove diameter. It shot very well with a bore riding style bullet. I seem to have better luck getting them to shoot if I match the chamber neck and bullet base to the minimum. At least for now anyway. Thanks, Squid Boy

"Squid Pro Quo"

Attached Files

Close