This is not news to many of you that have heard that nose damage is not critical to bullet accuracy but any damage to the base, especially around the perimeter of the base can have a significant negative effect.  Below is a link to a recent article that certainly proves the effects of bullet damage concerning high velocity jacketed bullets.  The same results apply to lower velocity cast bullets, which is the reason some reloaders choose to use a nose-pour mould.  But a good base-pour mould, snug sprue plate and good casting techniques will result in nice bullets with uniform undamaged bases.

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Wayne

Doesn't quite reflect my own 27 years of compeitive experience.

I am hoping that someone has done a test as to what level of minor defects a bullet can have without affecting accuracy. In the last few years I have had problems casting good bullets for some reason, ( zinc contamination I suspect) and I have been forced to shoot a lot of bullets which I would have previously rejected, out of sheer necessity. I have shot some pretty darn good groups with some of those bullets. I agree with the concept of shooting the best bullets you can possibly cast, but I think there is evidence that some minor defects  might not have a noticeable effect on accuracy. I know it sounds heretical, but there might actually be some truth to it. I have not done any scientific testing, which would require more time than I have available right now.
Joe S

Mick B wrote on May 29^th, 2020 at 9:52pm:


Mike,

Excellent point about the wad possibly eliminating the effects of a damage base.  I've heard that some cast bullet shooters do not use a wad at all.  In that case they should rethink their loading technique.  It was a long time ago but I have shot cast bullets without wads and without gas checks in .357mag and .445mag and noted base gas cutting damage.

Wayne

texasmac wrote on May 30^th, 2020 at 12:02am:

I saw all 5.  They each have a note about their defect.  No normal target displayed.

That’s an interesting experiment and I am all for people putting theories to the test, but......

If he had lowered the velocity, shot further placed a second target spaced a foot behind the first one, he might draw different conclusions. And because I’m kind of a jackass about these things, he should have the confidence not to repeat the test with nose damaged bullets and shoot with a suppressor attached allowing him to also check stability at the muzzle. There is a big difference between risking a sideways hole in paper and a $1000 baffle strike.

I have tested well into the hundreds of different bullets at sub and trans-sonic velocities and speed covers a lot of of issues. Slow moving bullets, spinning close to the low end of the stability factor show defects sooner than bullets over 2000 fps.

One last poke at the test would be a false sense of security. The Nosler partition is probably one of the toughest jacketed bullets on the market. I think that doing the same test with a thin jacketed varmint style bullet he would have had a few that never made it to the target because they would have come apart in flight.

I absolutely agree that the base generally will show problems sooner or more dramatically than the tip, but that does not mean it’s not there. Otherwise the BC/drop in the test would not have changed. 

The bullets with material removed gained muzzle velocity, lost BC. That is a sign of unstable flight robbing energy faster. While the bullets with displaced material retained the muzzle velocity, but lost flight efficiency.

It’s also worth noting that the bullet with the notch cut in the rear, retained the highest BC. Velocity at impact would be an interesting piece of data to also have.

Interesting to see someone actually put a so called myth to the test, I just hope it does need install a lot of misplaced confidence.

texasmac wrote on May 30^th, 2020 at 12:00am:


I believe Mike's statement might be directed at BP cast bullet shooting, since most who shoot smokeless cast loads do not use wads. Wads can create some dangerous situations when used with smokeless powders, so they normally aren't used. I sure wouldn't ever use a wad with smokeless powder.

marlinguy wrote on May 30^th, 2020 at 11:41am:


marlinguy,

Can you further explain why a hard fiber or poly wad between smokeless powder and the bullet might create a dangerous condition?

Wayne