velocity with accuracy

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Ken Campbell Iowa posted this 16 December 2014

it is looking as if our near-liquid lead alloy bullets are being distorted in the first inch or so upon ignition.  it is not as clear that running out of lube or stripping/gas cutting, or melting due to barrel friction  after the first 6 inches is unavoidably present.

partial success in out quest to match jb accuracy is probably due to schemes to align and support as much of the bullet as we can before firing. 

and probably by using as hard an alloy as we can find .. maybe the end goal would be a strong metal jacket ( g ) .

also it seems that keeping g forces lower ( thru slower burning rate powders and very long barrels ) results in less bullet deformation for the same muzzle velocity.  honorable mention goes to having a high quality barrel .

the above is an attempt to pause, inspect the past 600 years of shooting lead, and see where we go from here.  that we attain an easy 2 to 3 moa by following 4 or 8 rules i consider amazing !!  harry pope knew these rules 100 years ago but only with the internet have the rules been so available to so many interested in improvements.

as has been dutifully noted , and with precious truth indeed ... that wonderful schemes and midnight inspirations do not make great targets without some investment of time, sweat, ...and yes often money ... still it is useful to have a few hundred possible fantasy improvement scenarios in hand for our subconscious to sort out on our road to beating the curse of cast bullets always being that other child.

so what do we try next ?  accuracy with velocity is near ;;; i can sense it !!

ken  

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Ken Campbell Iowa posted this 16 December 2014

bullet hardness :: could we mix bronze pellets ( as in very small pellets used in sintered brass procucts ... available on ebay ) in our alloy ?

yep they would soon float ...but maybe stir and pour a bullet as a colloid. hey, hold the mold base up and let the pellets float to the base and produce a hard base softer point bullet.

and keep the poured mold hot for ten minutes to allow the pellets to slowly rise to the base.

what could go wrong ?

ken

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Ken Campbell Iowa posted this 16 December 2014

bullet support before ignition. ::

it would seem that a full cylinder, wadcutter bullet would be ( nearly ) fully supported design, so shouldn't we start there is support is the biggie ? yep, we expect that out there a ways air pressure would begin to win ... so what is the least angle of unsupported nose it takes to ... say ... attain reliability of impact ( accuracy ) at 50 yards ? 100 yards ? 200 yards ? at say 1600 fps.

different yardages are different games due to wind deflection .. but let us say zero wind velocity, only mass of air molecules screwing up our good intentions.

ken

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onondaga posted this 16 December 2014

http://castbulletassoc.org/view_user.php?id=40>Ken Campbell Iowa

How many times have you seen and continue to see people mention they use a beaked caliper in their muzzle to determine bullet diameter or those that finger push a bullet in the muzzle for the same feat? This is the worst kind of ignorance about cast bullets....these shooters believe they are correct and have actually made zero effort to fit bullets to the chamber throats of their firearms.

How many decades now has the Lee book directions for selecting alloy hardness to relate to load pressure been ignored?

There are unhelpable people that desire to be expert shooters with astonishing target results from cast bullets. Most will never change anything but they wholeheartedly expect their results to change. At this point, my best recommendation is to just say hello to them politely at the range and disregard all else about their closed minds and their hopeless existence and efforts to shoot a small group. Many of them just want to argue for the sake of arguing anyway.

Gary

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Ken Campbell Iowa posted this 16 December 2014

throat angle ... or how i hate compromises ...

let us say we have a bullet with one inch of groove dia bearing surface.

1) throat angle 0 degrees: we power breech seat and get full support. needs weird tools, impractical for hunting. but maybe least distortion ...

2) angle one side 1/4 degree with cylindrical bullet.. easier to seat but engraved fully only at front groove dia. of bullet ... base diameter barely engraved.

3) 1/4 degree per side and bullet is tapered 1/4 degree over grooves. bullet can easily be seated until it stops against the taper, but is not actually engraved until fired. the good news is that it only has to move 0.0002 until engraving starts ... and 0.004 inches later it is fully engraved, y the bore is sealed by the bullet.

note that if the bullet was hard seated about 0.004 after contact, it would be fully engraved before firing.

so how come we don't all use a 1/4 degree taper throat, a 1/4 degree tapered bullet, and a hard nudge seating after contact ?

is it that easy ?

and from above posts, a tapered wadcutter-45-degree-nosed bullet and a brass-filled alloy.. .. ( g ) .

what could go wrong ?

4) a 1/8 degree per side throat ... would too little taper not engrave enough to avoid gas cutting y slippage ? it would take 2 inches before our bullet is fully engaged. but then the engraving would be gentle if there is any advantage to that.

what could go wrong ?

ken

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Ken Campbell Iowa posted this 16 December 2014

crap ! after 50 years of casting, the above is still all i can come up with !!

help me out, foks ...

i gotta go cut some metal. time to do something ( g ) .

ken

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joeb33050 posted this 16 December 2014

onondaga wrote: http://castbulletassoc.org/view_user.php?id=40>Ken Campbell Iowa

How many times have you seen and continue to see people mention they use a beaked caliper in their muzzle to determine bullet diameter or those that finger push a bullet in the muzzle for the same feat? This is the worst kind of ignorance about cast bullets....these shooters believe they are correct and have actually made zero effort to fit bullets to the chamber throats of their firearms.

How many decades now has the Lee book directions for selecting alloy hardness to relate to load pressure been ignored? It seems to be a theory that's been disproved several times. As expected, since there's no reasonable data supporting it.  There are unhelpable people that desire to be expert shooters with astonishing target results from cast bullets. Most will never change anything but they wholeheartedly expect their results to change. At this point, my best recommendation is to just say hello to them politely at the range and disregard all else about their closed minds and their hopeless existence and efforts to shoot a small group. Many of them just want to argue for the sake of arguing anyway.

Gary

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onondaga posted this 16 December 2014

 There is not going to be a renaissance like rejuvenating rebirth with cast bullets coming out on top and shooting better than jacketed bullets by some yet untried cast bullet method.

To do well, just copy what works and do it as well as you can.

RE: Lee

Gary

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Hamish posted this 16 December 2014

onondaga wrote:  There is not going to be a renaissance like rejuvenating rebirth with cast bullets coming out on top and shooting better than jacketed bullets by some yet untried cast bullet method.

To do well, just copy what works and do it as well as you can"

Never let your grasp exceed your reach, never look beyond the next hill? How did we get to this point to know “what works"?  Didn't someone have to try something new?

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onondaga posted this 16 December 2014

http://castbulletassoc.org/view_user.php?id=8417>TheAmishGolfballShooter

” Didn't someone have to try something new? “

Yes, hundreds of years ago and you can read about it in the library. That is my point.

Gary

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pat i. posted this 16 December 2014

Gary, like Joe I'm sure you don't mind me editing your post a bit to keep things civil during the Christmas holiday.

This isn't directed at anyone personally but I'm really tired of the jabs on this forum. That bologna has basically ruined Cast Boolits and I don't want this one following suit. If anyone has a problem with me being a little heavy handed with the edit button from now on their best recourse is to contact the CBA board of Directors and bitch about me enough that they me remove from this lofty position as moderator. There's no reason to fight about something as insignificant as shooting cast bullets and, unless I get the boot, every time I see it starting I'm going to put an end to it from this point forward. I'll keep the good and relevant parts of a post but the bad's disappearing. I'd like everyone's help in keeping this place mellow by pointing out to me small fires before they turn into an inferno. There's enough of that going on in other places to satisfy anyone's need for drama.

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bjornb posted this 16 December 2014

Pat,your “heavy hand” is most welcome. I left the other forum due to lax moderating; the resident trolls were given free reins and every potentially interesting thread would soon spiral downward. Thanks.

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R. Dupraz posted this 16 December 2014

Thanks Pat.     It's long overdue. Maybe this place  can still be what it once was yet.   

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onondaga posted this 17 December 2014

http://www.castbulletassoc.org/view_user.php?id=5498>pat i.

You do a terrific job and thank you. I shouldn't take this stuff personally and rarely do. Plus, I enjoy spirited debate and will disclaim circular false logic and assertions for what they are. 

Gary

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Maven posted this 17 December 2014

"...or those that finger push a bullet in the muzzle...." Gary, That was no less a person than Robert Sears' recommendation for a quick determination of CB fit.  It has served me well enough, but there are exceptions and additions to Bob's methodology.

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delmarskid1 posted this 17 December 2014

I wish that I could afford a gain twist barrel with progressive depth rifling. My feelings re such that the soft cast bullets jump the threads when they hit the rifling. Deep straight grooves grading into the desired twist with more grip caused by decreasing depth of rifling nearer the muzzle. Neat trick huh?

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Ken Campbell Iowa posted this 17 December 2014

delmarskid1 ” bullet skidding when entering the rifling “

you would think that a washer or tube cast into the ogive .. where the forwardmost point that first hits the lands ... in factory chambers ... would help that. i had a 375 mold ... nei ...that took tubing ... but i gave up .. just too much hassle y cut tubing never fit well. results didn't fit a probability curve ( g ) .

a gas check on the back seems to help but maybe in a factory chamber the damage is done by the time the gas check arrives at the lands. hmmm . how about a gas check wadcutter shot backwards . gas check on both ends ? my head hurts.

ken

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joeb33050 posted this 17 December 2014

What notions I get from Bjorn and the other guys are these: Breech seating in bolt guns is part. I know it's been and is being done, but... No bore riders is part. Bore riders work for me, and I love 'em. It can be tricky matching alloy hardness for engraving, bumping noses, nose size as cast and OAL length to a particular gun. Veral doesn't like bore riders. Jacketed bullets aren't bore riders. Could bore riders be wrong? High velocity. Like a lot of others I read “Cast Bullets” and tried most of it. I never got paper patching or any high velocity to work. But---ther are now and always have been, on the edge, guys who shot HV with at least reasonable accuracy. So maybe the “new departure” includes these three. We'll see.    

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Larry Gibson posted this 17 December 2014

Breach seating is not necessary for accuracy at higher velocities. Some of us still go with fixed ammunition. BSing obviously does provide some benefits in the way of accuracy (still to be proven conclusively at this level of velocity and pressures)and case capacity.

Bore riders (old and “modern” designs) only hold up to a certain level of velocity and acceleration. Most of them have too much unsupported nose, too deep of lube grooves, a scraper groove and a poor bearing length to bullet length ratio. If you want to push into really higher velocities with cast bullets then bore riders are indeed wrong.

Many have problems with PPing and find it difficult to work at higher velocity also. Higher velocity with regular cast bullets while maintaining a reasonable level of accuracy is obviously possible as some of us are doing just that. The biggest reason it is being done at 2600 - 2800+ fps now is with the understanding of how RPM adversely affects the bullet in flight. By using slower twist barrels and properly designed bullets the adverse affect of RPM is controlled.

With a properly designed cast bullet for high velocity such as the NOE 30 XCB we can still easily attain reasonable accuracy at somewhat higher velocities than normally thought with 10 and 12” twist .30 caliber rifles. I just posted the results of such a test on the NOE forum. With the 10” twist 2300 - 2400 fps and with the 12” twist 2400 - 2500+ fps with reasonable accuracy of 1.5 moa +/- with 10 shot group is relatively easy to obtain. Once at that level then the loads can be tweaked for probable better accuracy.

With a longer (26” plus) barrel of 14” twist 2600 - 2800+ fps with that level of accuracy are also easily obtained. I've a 30” plus barrel with a 16” twist on the way so we shall see what that holds. The concept of longer barrels with slower twists has been around for a long time....Pope was using them. However, the “new departure” is using the longer barrels with slower twists with high velocity cast bullets.

LMG

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

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OU812 posted this 17 December 2014

Would a non tapered design work? All that is required is a throating reamer and sizing full length for a snug (.0001-.0005) fit inside long free bore. Sizing full bearing length would also remove most of mold offset created by two mold halves not aligning. This non tapered style bullet can be scaled up larger or down smaller for various calibers. Use the Greenhill formula to figure length needed.        

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tturner53 posted this 17 December 2014

Now you have made me curious. Two things; what's the story on this NOE 30 XCB? Who's idea and why? I'm all for accuracy and velocity, sometimes. Fun is fun. Also, this talk has me wanting to review the extensive work done by 'Molly' re. Cream of Wheat fillers. A slight detour here, I know, but he got good hunting accuracy and velocity with pretty simple loads. I've tried some of his stuff out and the COW does do amazing things. Clean is what comes to mind.

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