Will lapping a mold fix out of roundness?

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  • Last Post 07 November 2012
GBertolet posted this 02 November 2012

I had the opportunity to purchase a used Lyman 452374 2 cavity mold cheap. The bullets are slightly out of round, and about 1.5gr variation between the cavities. About 1.5 thousandths out of round to be exact,.4545 to .453.  Will lapping, using a bullet embedded with abrasive, true the bullet up, and maybe somewhat equalize the weight if used heavier on the lighter cavity? I'm using a .453 sizing die and it just covers the out of roundness. This bullet out of my 1911 doesn't really shoot that bad. Maybe this concern is much ado about nothing.

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onondaga posted this 02 November 2012

http://www.castbulletassoc.org/forum/view_user.php?id=1738>GBertolet:

It could help and you could also ruin the mold a lot worse.  You will need about 10 lapping bullets to lap both cavities evenly, more for any attempt to make the lighter cavity heavier.

Cleanliness during the procedure is the most important part. Any abrasive on the mold flats will add to out of roundness when you hone. Grit finer than 300 is pretty useless on aluminum and you are attempting steel. You will need a good abrasive that cuts steel. Oil carried abrasives like valve lapping compound will do the job but maintaining the level of cleanliness needed with an oil carried abrasive is a major job.

I use dental pumice carried with dish-washing liquid  on aluminum molds and rinsing out frequently with water is easy. You will have to rinse and brush with a solvent frequently or you will end up with a dismal failure.

.0015” out of round is closer than most get or hope to get from a cast bullet dropped from a mold. Consider getting inexpensive aluminum Lee molds to evaluate and if you decide to hone them it is vastly easier.

Also try shooting your bullets as cast with no sizing and just tumble lube, they will likely be more accurate on paper if they are large enough and function in your action.

Keep in mind that the most important factor in addition to diameter for an ACP is the fill-out of the base in plain based bullets like the  452374.

Gary

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John Alexander posted this 02 November 2012

"This bullet out of my 1911 doesn't really shoot that bad. Maybe this concern is much ado about nothing."

GBertolet,

There you have it. If you were able to make both cavities absolutely round and weigh exactly the same (which would be quite a trick) there wouldn't be any accuracy improvement that you could see with your 1911.

I have seen more than one bullet that much out of round average one inch for five shots at 100 yards out of good rifles. I.5 grains of weight difference in 245 grain bullets (much less than 1 percent) is also not enough to make a difference at the target.

John

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GBertolet posted this 02 November 2012

Thank you all for your opinions. The consensus seems to be, not to tempt fate and to just leave the mold alone, and be happy with what I have. I am inclined now to follow that mindset.

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.22-10-45 posted this 02 November 2012

Hello, GBertolet. In working with the earlier 49gr. version of the Lyman 225415..I was both plagued by out of roundness & undersized. I worked with this mould alot..making laps by drilling & tapping bullet for headless allen screw & using hex wrench to turn..using Cloverleaf coarse & fine lapping compound. I finially did get it pretty round & up to a uniform .225 dia. However, one day while casting..it occured to me that although the outside was round...those lube grooves would still be catywampus!

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Ken Campbell Iowa posted this 02 November 2012

this is so simple as making round cavities ...they might still not cast round  bullets.    most of our molds are rectangular....i am thinking a mold to make round bullets should be round on the outside ....and not have slots or heat sinking metal handles attached ....

in our business of making weird things, we had several dozen molds made ...  i am not a mold maker, but worked with some of the best ...it is much more complicated than making perfect cavities ...

just some thoughts ken

oh, an old pope mold i used to use was round ... 

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delmarskid1 posted this 02 November 2012

How bad do they look after sizing? May be much ado about nothing.

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GBertolet posted this 02 November 2012

The bullets look great after sizing. My .453 sizer just burnishes the smallest part of the bullet.

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linoww posted this 03 November 2012

I agree with John A. 100%.I have made a point to mark and shoot bullets that are wrinkled and out of round a bit and weight different etc..and they go right in the group with “perfect” bullets much of the time.Sometimes the off shot is with “good” bullets.

George

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Reg posted this 03 November 2012

linoww wrote: I agree with John A. 100%.I have made a point to mark and shoot bullets that are wrinkled and out of round a bit and weight different etc..and they go right in the group with “perfect” bullets much of the time.Sometimes the off shot is with “good” bullets.

George

Hmmmm.  Have often wondered about this.  Have run the same tests with the same results right down to that occasional “off” shot with a seemingly perfect bullet. I know that the serious bench shooters both old and new demand absolute perfection in their bullets but has anyone ran a few groups with a odd wrinkle allowed or a minor weight variation ? I am not talking serious variations, just the minor wrinkle or bit of out of roundness that for the most part will disappear with correct sizing.

Another thought.  If a mold were out of round all on one side ( a miss cut mold ) that bullet would be a bear cat to pound out of the mold.  The couple of out of round molds that I have played with drop their bullet with no more effort than a perfect mold telling me that the out of roundness is shared equally or nearly so.  Would not this business of being equally shared not cause much of a gyroscopic imbalance ???

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John Alexander posted this 03 November 2012

Not all serious bench shooters both old and new demand absolute perfection in their bullets. Absolute perfection is a pain in the neck, or somewhere, and not attainable at any rate. I stopped weighing my match bullets years ago after I satisfied myself that it didn't help. The last two years I have taken bullets that were over .001” out of round. Honestly I wish they were round. I would feel better but I an not sure that I would shoot any better.

I have written on this issue in the Fouling Shot off and on for over thirty years, but the facts (or at least what I find by testing) has little effect on the conventional wisdom. I guess this resistance is because the conventional sounds so reasonable. Just as the earth being flat sounded reasonable.

John

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LWesthoff posted this 04 November 2012

I give all my cast bullets a pretty critical visual check, and then weigh them and select from the top of the bell curve +/- a max of .25 gr. I also weigh all my cases and segregate them into groups +/- 1.5 gr., and weigh all my powder charges (electronic scale) to minus zero / plus 0.1 gr., AND I DO THIS KNOWING IT IS NOT REALLY NECESSARY!

I do it because I'm still learning how to shoot as accurately as I can off the bench. I do it so that if I have a flyer or two out of the group, I won't be tempted to blame the bullet or the load. I'll try to analyze what I did wrong.

Sure it's anal - but it's helping me learn to be a better marksman. I think it works for me.

Wes

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RicinYakima posted this 04 November 2012

Wes,

I agree with you! I may not be able to prove it on the target every time, but it sure makes me feel like the errors are mine.

Ric

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joeb33050 posted this 04 November 2012

3.7 DAMAGED BULLETS

One day in the summer of 2004, after casting some 311299 bullets, I emptied the container of bullets onto the concrete floor from a height of about 3 feet. After saying the obligatory words I was ready to re-melt the bullets and start again, but then thought that these bullets gave me an opportunity to experiment. I inspected and weighed the bullets, discarding any with casting defects or outlying weights, as I do with almost all my cast bullets. The acceptable dropped bullets had dents ranging from pretty bad to no dent at all. I rejected no bullet for a dent. I was working with a M54 Winchester in 30 WCF at the time. I loaded the dropped bullets and undropped bullets with the same loads, and shot them for group at 100 yards. Here are the results. GROUPS AVERAGE AVERAGE SHOT GROUP, GROUP, WITH DROPPED NOT DATE POWDER CHARGE EACH BULLETS DROPPED 8/4/2004 AA#9 12.5 4 1.569" 1.650" 8/25/2004 SR4759 12 4 1.181" 1.613" 9/8/2004 IMR4227 14.5 5 1.060" 1.290" 11/3/2004 AA#9 12.5 4 0.913" 1.019"

If I'm testing two loads, I shoot load “A” first, then load “B". Then I wait about fifteen minutes, may clean the gun if that is part of the test, and then shoot load “B", then load “A". This takes the “clean” and “hot” bias out of the testing. In each of the four tests, the dropped and dented bullets shot smaller average groups than did “perfect"= not dropped and dented bullets. I don't know what conclusions can be drawn from this experiment, other than that dents don't seem to radically degrade the accuracy of cast bullets.

To see if damaged bases affected accuracy, I took a box of 18 Hoch bullets for the 32/35 Maynard, and made one file pass across the bases at about 45 degrees. This filed a flat defect on the bases, readily seen. 2/23/05 12/IMR 4227, Rem 2 1/2, breech seated, multiple cases, Model 1882 Maynard No. 16 in 32/35, Iron Sights, Hot and plenty of mirage. 100 yards, 5-shot group with perfect base bullets, then 5-shot group with damaged base bullets-alternating for 3 groups each.
Group Sizes: Perfect bases: 2.15", 2.20", 2.675” Avg. 2.342". Damaged Bases: 1.2", 2.975", 2.025” Avg. 2.067” On a good day, with one case and going carefully, this rifle has made many groups under an inch, probably averaging about 1 1/2 inches. The Irons are harder to see than ever. Ohaus 45-405 bullets, 434.5 +/-.5 grains, Darr lubed, 21.5 grains SR4759, Dacron wad, WLP primers, breech seated, 100 yards, five shot groups, C. Sharps 45/70 Model 1875, 30X STS, Muzzle Clamp/Anti-Cant device.

A set of bullets had the bases filed at a 45-degree angle for about half the thickness of the base band. Shot 3/2/05 to see the effect of damaged bases. Windy enough to blow empty plastic ammo boxes off the bench, 70 degrees, bright sun, plenty of mirage. Alternating perfect and damaged bases.

Group sizes: Perfect bases: 2.1", 4.3", 2.05", 3” Avg. = 2.863" Damaged bases: 3.35", 2.675", 3.95", 2.9” Avg. 3.219" I thought there might be lead in the barrel, couldn't find any. I read through the notebook on this rifle last night. Many 10 shot 200 yard groups under 4", many 100 yard 5-shot groups under 2", some under 1", one measured .693"-all with this load. I've used the Wolf No-Grease-Groove bullet almost exclusively in this rifle since 1993. I don't know why I'm shooting such big groups in this damaged bullet testing-but here it is. Maybe these damaged bases caused the larger groups. 3/23/05, nice and windy, with gusts, varying from bright sun to rain showers. About 84 degrees with excellent high humidity. Martini 30/30 bench rifle, Lyman 20X STS, Wolf No-Grease-Groove 213 grain bullets with two coats of Lee Liquid Alox, 12.5/AA#9, Remington 2 1/2 primers. One hundred yards, five-shot groups, one sighter, shoot two groups, clean. Good bases 1.1", 1.6", 1.825” Average 1.508" Filed bases, 45 degree at the edge 1.325", 1.65", 1.075” Average 1.35" As an aside, I also tested 311299's from a “Beagled” mold, these averaged 1.069” for four groups with the same load. The Wolf NGG bullet has always shot adequately if not as well as other bullets in this rifle, but sometimes leads about a foot up the barrel-hence the cleaning. This is the third test. It starts to look like we can say that damage to the edges of bullet bases doesn't radically affect accuracy. 3/22/06 308403, Darr Lubed, Rem 2 1/2 primers, one case, 7/Unique, 30WCF M54 Winchester, 30X STS, Sandbag bench rest (Hoppes). 85 degrees, very windy, clouds then clear, very hot in the sun. 100 yard five shot groups. 26 bullets had the bases filed at a 45-degree angle to make a defect about half way up the base band. Fired about 6 sighters and stopped. Next relay (15 minute relays) fired 1 fouler, 5 filed base, 5 good bases. Next relay fired 1 fouler, 5 good bases, 5 filed bases. And so on, alternating the first group shot between filed bases and good bases. Filed Bases 2 .375", .825", 2.4", 2.5", 2.4” Average 2.1" Good bases 3.3", 2.55", 2.3", 2.2", 2.3” Average 2.53" There are a lot of bullets tipping. Maybe need more powder or Dacron; I've used 7.5 grains/Unique and Dacron in the past. This bullet generally shoots into about 1.5” averages at 100 yards. Maybe the wind, which will stop in July, when it gets REAL hot. Again, I don't think that filed/damaged bases shoot better than good bases, the .825” group is a fluke. 3/29/06 308403, Darr with some beeswax lubed, WLP primers, 7.2/Unique weighed/dribbled, Dacron wad tamped down on powder, 30WCF M54 Winchester, 30X STS, Muzzle clamp/anti-cant device, flat bench rest. 79 degrees, slightly windy, clouds then clear, 100 yard five shot groups. 26 bullets had the bases filed at a 45-degree angle to make a defect about half way up the base band. Fired 6 sighters and stopped. Next relay (15 minute relays) fired 1 fouler, 5 filed base, 5 good base. Next relay fired 1 fouler, 5 good base, 5 filed base. And so on, alternating the first group shot between filed bases and good bases. Filed Bases 2.55", 2.2", 1.5", 2.525", 2.85” Average 2.325" Good bases 1.125", 1.325", 2.3", 1.275", 1.8” Average 1.565" Most of the bullets are still tipping. Finally, the damaged base bullets shoot larger groups than the good bases. 4/5/06 308403, Darr with some beeswax lubed, WLP primers, 8.0/Unique weighed/dribbled, Dacron wad tamped down on powder, 30WCF M54 Winchester, 30X STS, Muzzle clamp/anti-cant device, flat bench rest. 84 degrees, quite windy, clear, 100 yard five shot groups. 27 bullets had the bases filed at a 45-degree angle to make a defect about half way up the base band. Fired about 6 sighters and stopped. Next relay (15 minute relays) fired 1 fouler, 5 filed base, 5 good base, cleaned barrel with 2 patches and MM oil. Next relay fired 1 fouler, 5 good base, 5 filed base, cleaned barrel. And so on, alternating the first group shot between filed bases and good bases. Filed Bases 2.2", 3.7", 1.95", 1.525", 1.275” Average 2.17" Good bases 1.7", 2.0", 2.6", 1.825", 1.675” Average 1.96" Maybe half of the bullets are still tipping. Those shot 4/5/06 were from a lot that weighed 170.6 to 170.9 grains. I just filed the base of one out of that lot. It started at 170.8 grains. After filing it weighed 170.5 grains. The filing lost .3 grains. 4/12/06 308403 lubed with Darr + some beeswax. 11/AA#9, WLP primer, CF Ventures soft gas check, Martini 30/30 bench gun, 30X STS, muzzle clamp/anti-cant device, flat bench rest. Five shot 100-yard groups, 1 sighter and 2 groups per 15-minute relay. Bases on some bullets filed at ~45 degree angle ~ half way up the base band. It was 82 degrees and windy. How windy was it? My Gatorade plastic bottle cap blew off the bench, my gun case blew open (it was slightly open) and a set of sky screens with holder and tripod blew over twice. I have little experience with this bullet in this gun. Six of 25 shots with both good and filed bases were tipping. Good bases 2.725", 1.175", .625", 1.45", 1.7” Avg 1.535" Filed bases 3.125, 2.675, 1.45", 3.45", 1.025” Avg. 2.345" Summary to date FILED GOOD BASES BASES
3/22/06 2.1" 2.53"
3/29/06 2.325" 1.565" 4/5/06 2.17" 1.96" 4/12/06 2.345" 1.535"

Damaged Bullets, Distinction and Difference After looking at forty groups fired, half with filed-base bullets and the other half with “good” = unfiled-base bullets, I've been assailed by a conclusion, to wit: Not all bullets with damaged = filed bases fly wildly to the target. The probability that any given bullet will land out of the group is greater shooting bullets with damaged bases. I first thought that this was a distinction without a difference-it's starting to look like bullets with damaged bases make bigger groups than bullets with good bases. But I think that I see a difference. All our bullets would go through the same hole, we think, if not for the differences that creep in amongst our loads. Differences in brass or bullet or powder or primer or bore condition or weather or any of the dozens of variables. These differences, some or most of us suspect, yield shots outside the group. And my assumption, shared, I think with others, is that if we assembled and shot a set of loads, all with a given difference, the groups would be larger than if that difference were not present. And we suspect that that is true because the differences make the bullets fly out of the group. Now all bullets with damaged bases do not fly out of the group, some of them fly into very nice groups and others fly into nice four-shot groups with a flyer, or three shot groups with two flyers, or.... Since the filed-base groups look to be larger, probably bullets with damaged bases make larger groups on average than do bullets with good bases. Think of two normal-looking overlapping distributions. This is where I get stuck. A bullet with a forty-five degree filed surface for about half of the height of the base band should fly to a different place than an unfiled bullet. And with no specific orientation of the bullet with the bore, these filed-base bullets should make a “big” group. There are any number of folks who can explain why these bullets should make these big groups. They do make bigger groups, on average, I think. But, why are some filed-base groups smaller than good base groups? Why doesn't every filed-base bullet fly out of the group? Why is this a probabilistic process? If damaged bullet bases cause the bullet to fly out of the group, why doesn't every damaged base bullet fly out of the group? A cartridge without a primer doesn't go off, and it doesn't go off every single time. There's no business about it doesn't go off 96% of the time, it doesn't go off. If damaged bases cause bullets to fly erratically, then every bullet should fly erratically. Every bullet. Perfect loads make one hole. Real-world loads make groups with the greatest density of the shots in the center, and reduced numbers of shots as the distance from the center increases. Dense in the middle, density decreasing as the distance from the center increases. Loads with an intentional defect oriented randomly should make groups that look like a doughnut, with maximum density at some distance from the center, diminishing both toward and away from the center. I don't think that they do. So, I'll make a bunch of filed-base bullets and fire them at one aiming point. Maybe thirty or so. And I'll fire a set of good-base bullets at another aiming point. I'm thinking that if I don't get a doughnuty looking group from the filed base bullets that maybe we need to re-think some of those explanations. 4/26/2006 M54 Winchester 30WCF, 30X STS, 12/AA#9, WLP primers, CF Ventures Soft Gas Check, 308403 lubed Darr + beeswax, muzzle clamp/anti-cant device and flat bench rest. 65 bullets had 45 degree filed bases to about half the height of the base band. A set of 18 cases had file marks put on the base and rim for orienting. A fouler was shot before each set of shots, at the center dot. Bullets were put in the cases with the filed bullet marks at 12, 3, 6 and 9 o'clock, four shots, and the cartridge was put in the chamber with the case base/rim mark at 12 o'clock. Then as precisely as I could put the bullet in the case and then the cartridge in the gun, bullets/filed bases were oriented each shot. Four with filed bases, four perfect bullets, then four with filed bases and four perfect bullets; with a sighter comes to 17 shots per fifteen-minute relay. 64 shots each with filed and perfect bases were made. All shot at 100 yards. The weather varied from sunny to rain, still to very windy. In the still sunny conditions there was a lot of mirage, and biting horseflies about the size of robins. Lots of “damn"s and slapping body parts. The damaged base group is 3 9/16” high by 4 11/16” wide, with no discernable pattern. The perfect base group is 2 7/8” wide by 2 1/2” high with the center shot out and outliers ~evenly distributed.

It is clear from the target that bullets with damaged bases do not shoot wildly, that many of the bullets cluster into a small group, and that the group/distribution is not doughnut shaped. This suggests that the mechanism decreasing accuracy is not one that operates every shot, but is probabilistic in nature.

More damaged bullets To damage some bullets for testing I took 26 of the 5/6/07 cast Borton Darr bullets weighing from 183.4-183.6 grains and with a small round file filed away 1 grain worth of metal from the middle grease groove area. I weighed each bullet, filed away until the weight had dropped 1 grain. All Darr lubed. Five groups of five shots at 100 yards each with perfect bullets and these damaged bullets was the plan.

Ten shots at 2 points of aim were enough for me. Bullets with a 1 grain hole filed in the side with a round file, at 100 yards, are not wildly inaccurate, 10 shots aimed at 2 points of aim were contained in an area 3” X 7", but there were no groups.
Now one grain is a lot, and is a sphere .088” in diameter. I suspect that this is larger than would be found in all but a very, very few cast bullets. I then prepared sets of 30 WCF cartridges with 314299 bullets; one set with perfect bullets, a set with .2 grain filed off, and a set with .5 grain filed off. Here is a picture of 314299 bullets with .5 grain round-filed off.

Winchester M54. 30WCF, 30X Lyman STS The load is: 314299 “No Dot", GC Alox lube, WLP, 12.5/AA#9, LOA 2.845"

"Perfect” bullets, Hard, cast 2/3/07, 199.4-200.2 gr., sized .309"

  • 1/2 grain bullets, same as above but 1/2 grain filed off as shown

-.2 grain bullets, cast 3/9/07, 194.7-195.0 grains, sized .312”

On Wednesday, May 16, 2007 I shot these test “filed-side” bullets at 100 yards, 2 foulers and 2 5-shot groups per 15 minute relay, alternating between the 3 test loads. Groups measured to the nearest .025” with a plastic ruler with .1” increments. Unfiled, “perfect” bullets: 1.4", 1.5”, 1.95”, and 1.475”, 1.825 “Avg. 1.63” Bullets with .2 grain round-filed off the side: 2.2", 1.35", 1.2", 1.95", 1.275” Avg. 1.595" Bullets with .5 grain round-filed off the side: .95", 2.75", 1.175", 3.15", 2.5” Avg. 2.105" I'm a little surprised at the “perfect” bullet groups; the 412 5-shot groups I've tested with this rifle and many powders/several bullets have averaged 1.466". This data and last weeks data suggests that variations in bullet weight may cause variations in accuracy; and that bullets with bubbles/holes may be less accurate than those without. All going toward the “Weigh bullets” question.

I repeated the tests on 5/23/07 and 6/20/07. Here is a table showing the results of the here tests:

Perfect Filed .2 gr.    Filed .5 gr.

5/16/2007 1.400 2.200 0.950 5/16/2007 1.500 1.350 2.750 5/16/2007 1.950 1.200 1.175 5/16/2007 1.475 1.950 3.150 5/16/2007 1.825 1.275 2.500 Average 1.630 1.595 2.105 % 100.0% 97.9% 129.1% 5/23/2007 1.300 0.900 1.750 5/23/2007 1.700 1.750 1.300 5/23/2007 2.000 1.300 1.250 5/23/2007 2.100 2.150 2.050 5/23/2007 1.800 2.050 1.150 Average 1.780 1.630 1.500 % 100.0% 91.6% 84.3% 6/20/2007 1.450 1.900 2.400 6/20/2007 1.950 1.975 2.050 6/20/2007 1.450 1.750 2.450 6/20/2007 2.350 1.350 2.425 6/20/2007 1.750 2.800 1.250 Average 1.790 1.955 2.115 % 100.0% 109.2% 118.2% Grand
Average 1.733 1.727 1.907 % 100.0% 99.6% 110.0%

Group sizes were measured with a plastic ruler graduated in tenths of an inch. Resolution of group size was to .025” increments. All three-place decimals were formatted for consistency and ease of reading. These three sets of groups were shot on three different days under three different sets of conditions. If the grand averages are an indication of the process, then there is no “real” difference in group size for groups shot with “perfect” bullets and bullets with .2 grain round-filed off; and there may not be a “real” difference in groups shot with perfect bullets and bullets with .5 grain round-filed off. In order to confirm that there is a difference in accuracy between “perfect” and “.5 grain” bullets, with 90% confidence, 28 groups with each bullet would be required. For 95% confidence, 47 groups, each, would be required. Now these groups should be shot with bullets, powder, etc. from the same lots, under the same conditions. I'm not going to do it, and suggest that the results of this test can be summarized as follows: "In gun/load/etc. systems with capability to shoot 100 yard groups averaging 1.75” or greater, filed grooves on the sides of the bullets of up to .5 grain simulating holes only slightly increase average group size." Note: A lead sphere .05” in diameter weighs .2 grains, .a 07” diameter sphere weighs .5 grains. These are pretty big holes or bubbles to imagine in the bullets.

DAMAGED 22 RIMFIRE BULLETS
Here's a picture of 22 RF bullets with .3 grain filed off. Cartridges were prepared with .1 and .3 grains filed off with a triangular file. On 6/27/2007, Model 12/15 BSA Martini, Lyman STS 30X, 50 yards, windy and starting to rain in fits. Perfect, .1 grain filed, .3 grains filed ammunition. This gun, like the rest, loves Eley Match ammunition. I was going to file some Eley Match Red Box, I had the file in one hand and the first cartridge in the other, but a force stronger than I, (and I am enormously strong), kept me from touching that Eley cartridge with the file. I was able to file the PMC Match Rifle, this ammunition works well in this gun. Group sizes, leaded edge to leaded edge - .244", all in “ Perfect -.1 gr. -.3 gr. .433 . 473 .353
.382 .564 .324 .439 1.294 .394 .419 .732 .546 .547 .443 .910 Avg. Avg. Avg. .444 .699 .505 Here's the target: As an aside, thirty cartridges had an average weight of 51.9 grains and a standard deviation of .228 grains. Thirty empty cartridge cases had an average weight of 9.8 grains, and a standard deviation of .07 grains.

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Reg posted this 04 November 2012

joeb33050,

Excellent and I do mean excellent write up. Am printing it off and will put it in my copy of Mann's book. Just like in Mann's writings you pose a problem and two things come up to say no, it may not be-- but then again !!!!! I think it proves that after all these years we are still chasing that perfect ( repeatable ) group. Again, great write up.

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John Alexander posted this 04 November 2012

Joe,

Thanks for taking the time to give us so much in the way of results of a lot of careful experimenting. Our sport needs a whole lot more of this kind of methodical testing and reporting of results if we are to get beyond the the myths and beliefs that hold us back and waste time and effort that could be better spent.

Your post was a little like drinking from a fire hose but well worth the effort. I appreciate your work in reporting the results of a lot of careful testing. I believe it should go a long way in making thoughtful shooters skeptical of some of our time honored beliefs -- but then I tend to be optimistic.

Your results should also make any thoughtful shooter see just how many groups it takes to reach sound conclusions. Otherwise we would have to believe, for instance, that a .3 grain filed defect in a 22rf bullet makes it more accurate than ammo with a similar .1 grain defect. This should make shooters skeptical of drawing conclusions from a small number of groups -- which most of us do all the time. We can't shoot dozens of groups every time we want to test a load variation but we should be careful about drawing conclusions from small samples.

Thanks for taking the time to report the work

John

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John Alexander posted this 04 November 2012

Wes and Ric,

You have both given good reasons for weighing and careful visual sorting of bullets. After all, confidence in what one is shooting is important for good results. Also, this is our hobby not something critical to national defense and we ought to be able to do it in the way we like.

I am not advocating that everybody stop weighing bullets or stop discarding bullets with small wrinkles, although I suspect most could without enlarging their groups. All I am saying is that I have proven to my satisfaction that it doesn't improve my groups and I have stopped doing it.

I should stay humble for another reason. Most of my experience is with 22 caliber bullets. Maybe larger bullets have more, or more off center, bubbles and voids. Bob Birmley made a good case in the FS a few years back that he was finding surface voids that affected his groups.

I do think we should take it easy on telling new shooters that they must have perfectly round, uniform weight, and defect free bullets, perfect crowns, cases sorted by weight, weighed powder charges, etc. This long list of do's and don'ts can be intimating to new shooters and may drive off many that would stick around and enjoy our sport. As far as I know none of the above have been proven to be needed by logical testing in order to achieve pretty good levels of accuracy.

Joe's recent post should make us reexamine our belief that small (or even pretty big) imperfections and far less than perfect bases cause wildly inaccurate ammunition.

John

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LWesthoff posted this 04 November 2012

Actually, believe it or not, I agree with John Alexander. Do whatever gives you the most fun. For me. fun is trying to learn how to put 'em all through the same hole (with a Production class rifle) or put 10 consecutive rounds in the 10 ring with my Issue '03-A3. There's one guy at our club who comes out there with different issue military rifles and literally buckets full of surplus military ammo and never puts a target up; just shoots at the 200 yard gong (and hits it every once in a while). We're both having fun, but what he's doing wouldn't turn me on even a little bit. For the rifles I compete with, I index every round AND every bullet, but I sure don't bother trying to do that with my hunting rifle, and off the bench, it'll generally keep ten rounds within a couple of minutes.

Do whatever gives you fun; that's what this is supposed to be all about.

Wes

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RicinYakima posted this 04 November 2012

I am with you Wes! I have just as much fun shooting the “bunny gun” in 32 S&W long at sage rats at 25 yards as I don trying to put 10 cast bullet into an inch with the 03A3. And yes John, it is mainly about confidence. I hate guessing about 3 or 4 variables trying to solve a problem, just one at a time. Ric

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Chargar posted this 05 November 2012

I have yet to see a bullet mold that was 100% dead nuts on round. They do vary on just how much they are out of round. Always remember that any bullet will be the same size as the barrel once it have traveled it length in the barrel. It takes the most precision barrels to be perfectly round and most regular barrels are out of round to some degree.

I have been shooting long enough not worry about things, until the target tells me it is time to worry.

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Ken Campbell Iowa posted this 05 November 2012

hey joe::   you are the man !   thanks for the effort !

humbly, i offer a couple of interesting ( to me ) things...

1)  back when my 222 wuz shooting a lot of 1/2 moa with good mj loads ... i bot some cheap, advertized as seconds ...(   not the same as excellent factory blems from sierra or hornady .. ) ,,,the were jordan brand, as i recall ...anyway these were visibly perfect, wt. was consistent ...but the shot mostly 2-3 moa ...never figured out what was “bad” about them.

2)  for a while, i did a base lathe cut on lots of 22 & 7mm castered bullets ... it made a lot of them better....thickened the density in the center of the groups...but the overall group was about the same ...i am guessing the “outliers"...were so bad that the improved bases just couldn't  overcome ...  whatever  ..what actually went wrong ....  i never figured this out either (g). 

3)  because improving the center density of groups does mean something....i think it would be good to use one of the modern computer programs to decode shooting results ...mean radius from center of group ...

4)  and like most here, i still wake up at 3 am and try to figure out why castered don't shoot as well as store bot mj bullets ...

thanks again, joe redeeming social value is hard to come by ...(g) ken

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