What is the Most Promising Aspect of CB Rifle Shooting for Improving Accuracy?

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John Alexander posted this 18 January 2020

CBA has been partially responsible for the progress we have made in shooting CBs in fixed ammunition (as opposed to breech seating) over the last forty years but that progress has mostly stopped.  Those shooting specialized custom rifles with no restrictions cannot consistently shoot aggregates of 5-shot groups much under 0.5" at 100 yards.  Those of us who like to shoot unmodified factory or old military rifles cannot consistently shoot 5-shot aggregates much under 1.0" at 100 yards. We have been able to shoot to this level of accuracy for at least ten and maybe twenty years with little improvement.

The first of the four stated "purposes" of the CBA on the back of every Fouling Shot says: encouraging experiments that will improve the accuracy and effectiveness of the ammunition and increase the satisfaction and enjoyment of shooters. Many, probably most, of us that shoot CBs in rifles want to improve either to enhance our competitiveness if we like to shoot in matches or simple to do better for field use or personal satisfaction if we don't. 

What is the best way to achieve that improvement?  Up until now many have thought that uniformity was the road to improvement.  Ever more uniform weights of cases, powder, bullets, even gas checks and primers, ever more uniform sizes of bullets, flash holes, primer pockets, ever more cleanliness of bores, case necks, primer pockets and inside cases. Other efforts at improving uniformity have included using only one case, using nose pour molds or turning bases to achieve perfect bases, shooting bullets in the order they were cast, indexing bullets, cases and even primers.

It is hard to argue against uniformity but easy to see that more and more isn't always better and some of the above have been grossly overdone and achieved nothing.  Many of our best shooters have found many of the extreme attempts for uniformity listed above were worthless and have abandoned them. 

Paul Pollard has asked in the thread on factory ammunition what should we be working on to improve?

Because we have already tried pursuing uniformity to the point of foolishness, that approach doesn't look promising for future improvements. I hope we can start a discussion on what are some of the promising ways that should be explored in order to shoot CBs more accurately? What do you think?

John

 

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RicinYakima posted this 18 January 2020

IMHO, a better material to make the bullets out of besides lead. As a new guy only doing this for about 24 years, I have followed every thread I could find plus reading every book I could find back to the 1890's. We seem to have reached the point that our lead alloys are not capable of handling the stress of being a bullet and fired more accurately. The leaders of the lead-free movement are looking at home castable bullets that do not contain lead. That is really unexplored territory.

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David Reiss posted this 18 January 2020

I think the new coating is one aspect that has not been fully explored. We are just starting to experiment with the PCs, but true data under scientific conditions has not been done. Dan Lynch at Mountain Molds has been experimenting with different coatings with some success at high velocities. 

It is easy to believe there are many more coatings out there just waiting to be tried.

David Reiss - NRA Life Member & PSC Range Member Retired Police Firearms Instructor/Armorer
-Services: Wars Fought, Uprisings Quelled, Bars Emptied, Revolutions Started, Tigers Tamed, Assassinations Plotted, Women Seduced, Governments Run, Gun Appraisals, Lost Treasure Found.
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joeb33050 posted this 18 January 2020

IT'S THE BULLETS!!!!!!!!!!!!!!

ZINC?

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GWarden posted this 18 January 2020

One of the biggest things for me, and again each rifle is an individual has been alloy mix. I stumbled, and that is how it happened on trying a mix of 15#pb+25# mag shot+2% tin. I had and still try other mixes and none, I mean none come close in my 30cal & 6MM.  As noted in someone else might try this mix and get the opposite results. This has been the best in my 3- 30cal & 6MM Rem.

Bob

 

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Larry Gibson posted this 18 January 2020

I believe Joe is correct....it is the bullet.  Understanding that imbalances in the bullet during the external ballistic phase (bullet flight) are the reason we shoot groups instead of all going into the same hole.  In flight, if the center of form, center of gravity and center of spin do not coincide in the longitudinal axis then the bullets will vary from the intended flight path...i.e. shoot groups.  Then we also have the center of pressure and it's relation to the center of gravity and center of form in the lateral spectrum.

We can do all the things John mentions to ensure our cast bullets are about as perfect and consistent as possible.  However, we can not control exactly the balance of the difference metals during solidification or the control slight differences in the shrinkage during solidification.  Thus there will always be slight imbalances in the bullet no matter how well we think we cast.  We can not control the precise loss of lube on exit from the muzzle and during flight.  Then are we sure the GC is really consistent and balanced or do we just assume it is(?).  Additionally we can not control precisely the unbalancing affect acceleration has on the bullet during the internal ballistic phase.  Perhaps it's just the nature of a cast bullet and we've just not accepted that(?).

An occasional really small group will be shot now and then when the Sun, the Moon and stars all line up...…. but to consistently shoot such really small groups may not be in the cards.  Those really small groups John and everyone else searches for are anomalies...…...not saying we should quit searching for an answer but the question of just how consistently accurate (or precision) can we shoot cast bullets may already have answered.....

LMG

 

Concealment is not cover.........

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45 2.1 posted this 18 January 2020

CBA has been partially responsible for the progress we have made in shooting CBs in fixed ammunition (as opposed to breech seating) over the last forty years but that progress has mostly stopped.  Those shooting specialized custom rifles with no restrictions cannot consistently shoot aggregates of 5-shot groups much under 0.5" at 100 yards.  Those of us who like to shoot unmodified factory or old military rifles cannot consistently shoot 5-shot aggregates much under 1.0" at 100 yards. We have been able to shoot to this level of accuracy for at least ten and maybe twenty years with little improvement.

Granted, that we would be the CBA shooters in CBA matches. That leaves a large void you don't take into account and that doesn't include me either.


Because we have already tried pursuing uniformity to the point of foolishness, that approach doesn't look promising for future improvements. Correct! I hope we can start a discussion on what are some of the promising ways that should be explored in order to shoot CBs more accurately? What do you think?

John

 First of all, you all have tried the commercial bullets till everyone who does better has modified them in some way to do so. Most commercial bullets are undersize until they are fully in the barrel. If you are intent on shooting them, you need to use a soft alloy and a powder with a soft push and long pressure curve to get them in the barrel straight.

You need to try something else than what you are doing.... like a custom design and an alloy suitable to the load level you're trying. Harder is NOT better even though you guys really like linotype, it just isn't delivering great groups.

For you 308 shooters, I will give you a recipe for success. Try this alloy: 1/2 wheelweights with 1/2 dead soft lead (recovered factory wadcutters work fine) cast at about 725 degrees with a pot and ladle. Do not add anything to it! The sprue should set in about 3.5 to 4 seconds. Adjust the temperature until it does. Once there water drop them. Wait at least two weeks until you size them at 0.311" with Hornady gas checks with a "low viscosity lube" (that's important). The mold to use is this: https://www.mp-molds.com/product/mp-308-hunting-hp-gc/ with the hollow point pins. That bullet is dynamically designed for accuracy. The powder charge is 21.0 grains of SR4759 which will give you about 2,100 fps.

I shoot that in a stock factory stainless Ruger Gunsite Scout. That's my hunting load, but will do quite well on a target... at long range. It certainly beats the accuracy levels posted above by quite a bit.

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John Alexander posted this 18 January 2020

45 2.1,

Thank you for sharing your alloy, casting technique, and load information for the 308.

Would you please elaborate on "dynamically designed for accuracy"  What does that mean?  Who can do this type of design work for another caliber for us? Can you please suggest a reference where we can learn more?  Thanks.

John

 

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45 2.1 posted this 18 January 2020

45 2.1,

Thank you for sharing your alloy, casting technique, and load information for the 308. There is a lot more than meets the eye on manipulation of alloy, casting and loading than what is portrayed there.

Would you please elaborate on "dynamically designed for accuracy"  What does that mean?  Some background... for example, we have Barlow type two diameter bore riders, Ardito and Eagan type cone in cone, and various tapered designs. Various problems arise with each type. People assume that a matching taper will shoot great. Ardito matched exactly with a reamer with the same specs (lathe tail stock and matching taper style) as the bullet... the problem there is starting it without deforming it, hard to do with soft alloys (which lino is at the pressures he used with a velocity pressure limit), Barlow types have room to move sideways when starting to move. The Eagan is tapered (how I'm not sure), and have a good reputation, but I don't see high velocity goodness for them posted. These types basically fit the throat to some degree while at rest (which I call static fit)..... what happens to there alignment upon ignition is another story. If they gave under 1/2 MOA accuracy all would be good, but again I don't see it. Dynamic design involves making the bullet stay aligned throughout the process from ignition thru full engagement down the barrel.... basically the bullet self aligns and stays that way, even if you jump it to the rifling like any semi automatic requires to operate safely. That process involves gradually engaging the rifling (so to speak as the time interval is measured in milliseconds) as it travels the first inch or so of travel. Simple concept, but hard to understand and make work. For the 30 caliber I used about 30 data sets for new to worn throats measured to +/- 0.0001" along there lengths at short intervals or where the taper changed on lead impact slugs. The design comes from advancing the bullet profile along these plots (AutoCad on different layers). There are places where all the plots converge then diverge along the length.    Who can do this type of design work for another caliber for us? Me.... Can you please suggest a reference where we can learn more? There aren't any other than mine in print as far as I know. The man who makes the molds is Miha Prevec who owns MP Molds. I'm the major designer of a large part of the mold s he produces.  Thanks.

John

 

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Bud Hyett posted this 18 January 2020

I know jacketed bullet cores are formed from extruded lead wire. In discussion with these bullet makers, they emphasize their determination to have uniformity in the wire. 

Note; When an object cools, it shrinks.

  • If a cylindrical object cools, this draws the circumference smaller.
  • If a rectangular object cools, this draws the dimensions smaller.
  • If either shape has a hole through the center, is heated and cools, the hole dimension becomes smaller as the object is heated by cause of expansion and becomes larger by the cause of cooling. 

Question: What happens within the interior of the bullet as it cools? 

  • Is there a migration of the alloy toward the external surface?
  • If there is a migration, is the center less dense and less uniform?
  • Will a center that is less dense and not uniform influence the path of the bullet? 
  • Can we casters even test this?   

I have run this through my mind several times and cannot think of a method to test this. Is the alloy in the bullet denser toward the surface and less dense in the center? Does this happen in a large enough factor to influence the bullet's path? Does not happen in a manner to enable testing?

There is a physical chemistry technique that can track the location of an element within an alloy, this is extremely costly. This technique was used by metallurgists in the 1970's to track element locations within an alloy in the quest to build better alloys used in defense and space. 

Wikipedia reference

With this concept in mind, I keep the casting alloy clean. I have often wondered if dropping bullets directly into cold water would freeze the alloy movement and bring greater uniformity. 

Your thoughts, are we chasing windmills? 

Farm boy from Illinois, living in the magical Pacific Northwest

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45 2.1 posted this 18 January 2020

  

I have run this through my mind several times and cannot think of a method to test this. Is the alloy in the bullet denser toward the surface and less dense in the center? Does this happen in a large enough factor to influence the bullet's path? If you have a homogenous alloy, it wouldn't matter as it would be the same all the way around. The bullet would still be concentric. Does not happen in a manner to enable testing? Empirical testing. Air cool, water drop and heat treat to different hardness-es and test by grouping.


With this concept in mind, I keep the casting alloy clean. I have often wondered if dropping bullets directly into cold water would freeze the alloy movement and bring greater uniformity. It seems to do that. I've done it with different alloys over the last 30 years and it seems to work. The methodology has a relatively tight alloy temperature requirement. You need to be relatively near freeze temperature.... hotter alloy temps hardens the center too much. Beyond that I don't know.

Your thoughts, are we chasing windmills? No, you're not..................

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Tom Acheson posted this 18 January 2020

Might have to watch out for the credence we give to water dropping bullets. The hardness of each bullet will vary from other bullets handled a similar way during the session. Our cadence in opening the mold and lining up with the bucket will vary from bullet to bullet.  If we want all bullets in a session to have a chance of being close to the same hardness, heating ALL OF them up in the oven simultaneously and then move them ALL TOGETHER into a large container (sink next to the oven?) of cold water. The oven temp is around 10 degrees below the bullet slump temperature and the batch of bullets are often in the oven for about 45-minutes.

I’ve seen guys write that they store those bullets in the freezer to retard the bullet’s return to the non hardened state. 

Lots of theories on this!

How about a different variable.....the shooter and his skill, mindset, health, etc. the day of his range testing? Unlikely those factors are exactly the same on each range trip.

Tom

 

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Paul Pollard posted this 18 January 2020

45 2.1 said: Wait at least two weeks until you size them

I probably need to go back to bullet casting school, but what is the importance of the 2 week waiting period before sizing? Does the bullet retain its size better at this time instead of sizing the same day?

Thanks

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45 2.1 posted this 19 January 2020

45 2.1 said: Wait at least two weeks until you size them

I probably need to go back to bullet casting school, but what is the importance of the 2 week waiting period before sizing? Does the bullet retain its size better at this time instead of sizing the same day?

Thanks

Antimony dendrite growth......... Antimony grows a lattice structure as long as the Tin content is a lot lower than the antimony content. While doing that it also gets a little larger and harder. You need to wait for it to slow down and stabilize some. Of course the longer you wait the better they usually shoot.

 

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shootcast posted this 19 January 2020

I agree with Tom that on any given day there are always conditions that effect our ability. These range conditions probably have more to do with it than any other factor. How many times have you worked up a particular combination, alloy, Bullet , lube, powder charge and overall cartridge length. You think you found the best possible combination it shoots very well. So when you go home you duplicate everything to the best of your ability. Same alloy, same loading process. After all you wrote everything down. Next trip to the club or worse yet the match and everything changes. Imagine that ! . 

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jr460 posted this 20 January 2020

CBA has been partially responsible for the progress we have made in shooting CBs in fixed ammunition (as opposed to breech seating) over the last forty years but that progress has mostly stopped.  Those shooting specialized custom rifles with no restrictions cannot consistently shoot aggregates of 5-shot groups much under 0.5" at 100 yards.  Those of us who like to shoot unmodified factory or old military rifles cannot consistently shoot 5-shot aggregates much under 1.0" at 100 yards. We have been able to shoot to this level of accuracy for at least ten and maybe twenty years with little improvement.

The first of the four stated "purposes" of the CBA on the back of every Fouling Shot says: encouraging experiments that will improve the accuracy and effectiveness of the ammunition and increase the satisfaction and enjoyment of shooters. Many, probably most, of us that shoot CBs in rifles want to improve either to enhance our competitiveness if we like to shoot in matches or simple to do better for field use or personal satisfaction if we don't. 

What is the best way to achieve that improvement?  Up until now many have thought that uniformity was the road to improvement.  Ever more uniform weights of cases, powder, bullets, even gas checks and primers, ever more uniform sizes of bullets, flash holes, primer pockets, ever more cleanliness of bores, case necks, primer pockets and inside cases. Other efforts at improving uniformity have included using only one case, using nose pour molds or turning bases to achieve perfect bases, shooting bullets in the order they were cast, indexing bullets, cases and even primers.

It is hard to argue against uniformity but easy to see that more and more isn't always better and some of the above have been grossly overdone and achieved nothing.  Many of our best shooters have found many of the extreme attempts for uniformity listed above were worthless and have abandoned them. 

Paul Pollard has asked in the thread on factory ammunition what should we be working on to improve?

Because we have already tried pursuing uniformity to the point of foolishness, that approach doesn't look promising for future improvements. I hope we can start a discussion on what are some of the promising ways that should be explored in order to shoot CBs more accurately? What do you think?

John

 Hello all If I under stand the question correctly posted by John Alexander How to improve accessory with cast bullets  I have found over the years to  free float the barrel and use Limb savers at least 2 on a barrel  the easiest way is to start with one just in-front of the forend and the other about one inch behind the muzzle shoot at 50 yards three or 5 shot groups.Then move both toward each other one inch at a time you will see the group move bigger some times left or right and then start to come together once you have found the sweet spot just leave the limber savers their a lot of things are happing with the limb savers mainly you are adjusting the harmonics of your barrel with that load I have found using food grade spray silicone is the best way to slide the limb savers up and down the barrel .Now the limb saver trick can not be used on a military barrel which is covered up with wood may be one limbsaver by the muzzle or fix a bayonet to the bayonet holder you are playing with the harmonics of your barrel . This year I am going to use the limb savers and I have switched over to the RCBS AR sires of reloading dies along with a lee collet die and have been getting some very good results The tapper crimp die in the AR die set is great for taking out the Lyman step created by the M expand die I have set the tapper crimp so it will take out the bell in the case neck and not leave a mark on the cast bullet then I check the bullet to make sure it can not be pushed back into the case by putting the nose against the table and pushing down hard  if no movement it is set correctly. I will start another topic on this new loading way of loading fixed lead ammo latter on.

Have fun experimenting with the limb savers 

David Williams

  

 

 

1000 yards easy

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John Alexander posted this 20 January 2020

shootcast points out: "You think you found the best possible combination it shoots very well. So when you go home you duplicate everything to the best of your ability. Same alloy, same loading process. After all you wrote everything down. Next trip to the club or worse yet the match and everything changes. Imagine that !.

++++++++++

Most of us have had similar experiences.  To some extent these experiences show us that we have more to learn about how conditions (temperature, wind, mirage, humidity, elevation, phase of the moon) affect our groups.

More often I suspect it shows  that we don't shoot as well some days as on others. I know that in spite of my practice, dry firing, etc. I don't.

Perhaps even more likely than either of the above it may simply be the large natural variation between groups (even when everything is identical) has led us to a false conclusion. We tend to forget, or refuse to believe, that in a string of five 5-shot groups the largest group will be twice as big as the smallest almost half the time.  So if you are making a judgement by looking at single five shot groups, or even a few, those groups may easily be much bigger than average -- or much smaller, leading to wrong conclusions. Of course this doesn't apply if you are comparing one match, or a many group session to another.

FWIW

John

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hanover67 posted this 25 January 2020

"We don't shoot as well on some days as on others."

This thread has touched off some thoughts about the questions and answers so here are some irreverent observations.

I used to shoot in Highpower matches. Over 30 years my performance improved with a better rifle, better reloading technique, and enough match shooting that it qualified as practice as well. So one answer to better groups might be: Practice. I found that more improvement became harder and harder to achieve. The pyramid gets narrower at the top, and I eventually levelled off.

As to letting bullets rest for two weeks before sizing them, I agree. While I didn't know about antimony lattices until I read this thread, I had heard of lead resting before. I used Sierra 190gr Matchkig bullets for the 600 yard stage. Then I bought some 190's from Bob Cateruccio who made them in San Francisco. He said he cut his own lead wire and let it sit in the bullet jackets for enough time to stabilize. He said "Sierra doesn't have time to do that," and claimed I would get groups half the size of Sierras with his bullets. I did get better scores - not sure about group size.

I'm 77 and from comments posted on CBA forums I feel right at home age-wise.  I'll bet that if you could assemble a group of tech-wise 25 year olds and had them devote their efforts to bullet casting we would be amazed at what they would come up with. The achievements of the bullet casting community so far have been pretty amazing and the practices of reloaders in general have spilled over into the commercial manufacturers who now make much better ammunition and rifles.

I cast bullets in a pretty basic setup and I shoot for fun. I enjoy learning about exotic advances and results in the cast bullet fraternity, even knowing I'll never duplicate them.

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M3 Mitch posted this 25 January 2020

Anybody who can make a significantly better target bullet than a Sierra Matchking is an unusually good bullet maker!

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Ross Smith posted this 25 January 2020

Ted Williams said it best "Practice,Practice,Practice".

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John Alexander posted this 25 January 2020

We do have bad and good days shooting caused by the shooter. And bench technique and lots of practice is very important for some of our classes especially the military rifle and hunting rifle shooters. I shoot a 6 pound rifle with a round bottom forend and don't even know all the ways I can screw up.

But let's not kid ourselves that it is very hard to shoot groups much smaller than .5" with the type of equipment used in our classes that allow custom benchrest guns -- if the gun and load will do it. The first time I shot a 10.5 pound, full fledged, jacketed bullet benchrest rifle I repeatedly shot groups in the quarter inch range and anybody reading this could also do it if conditions are good.

With a flat bottom forend, guidance fore and aft, a two ounce trigger, and up to 30 pounds of mass it ain't hard and lack of practice isn't the problem (with the exception of coping with wind, mirage, etc.)

The problem is making that type of rifle do it with cast bullets, thus the .5 moa barrier -- unbroken so far.  

As Ken mentions cast bullets probably change shape when fired, They are much softer, non-elastic, and easier to distort than JBs. They are affected by fouling more and we burn a lot of lube contributing to the fouling.  Most bullets currently used in competition have a blunt nose even we know that BC is important. Somewhere in those or other differences with JBs is the answer as to where we should spend our time and effort.

It isn't going to be from picking more nits or using one case -- we have tried all those.  We have been like the drunk looking for his dropped car keys under the street light instead of nearer where he dropped them because the light was better.  Where should we be looking?

John

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