loads keyholing in colt, but not kimber

[FlyinBryan]

just loaded up some 230g cast rn bullets the other day and when my bro and me fired them at 15 yd targets they were keyholing badly from his 1991a1, but not at all in my kimber pro carry2. upon inspection, the targets looked like he was hitting nose first, but still keyholing almost every round.

my bud showed up and was shooting them ouyt of his colt defender with some keyholing as well. my kimber never did.

the loads were as follows:

230g cast round nose bullets
5.0g hp38
1.250 oal.

like i said it looked like they were all hitting nose first.

can this damage the gun that its happening in?


we fired some 225g flat point cast the week before and didnt notice this.

 

[ReloaderFred]

It sounds like the either the bullets are undersized for the Colts, or the Colts have oversize bores, which is basically the same thing. With cast bullets, the general practice is to load a bullet that's .001" over bore diameter. If the bore slugs at .452", then the ideal bullet would be .453" in diameter.

With that said, it's possible your Kimber bore runs on the small side, or has deeper rifling, which would allow it to better grip the bullet. It's not common to have .45 acp bullets keyhole, but it does happen. I've seen it more often in 9mm pistols, where the bullet was undersize.

I would slug the bore and then measure the bullets. That will give you a starting point to look for the problem.

As to your question about harming the pistols, the answer is it won't harm them. The bullet is getting down the barrel ok, but isn't getting the spin it needs to stabilize. You'll probably notice more than usual leading, though, since the bullet is probably bouncing from side to side as it travels down the bore, depositing lead along the way.

Hope this helps.

Fred

 

[Master Blaster]

It could be happening in the Colts because they have an excessive buildup of fouling, or shallow rifling.

I own both Colt 1911's, and Kimber 1911s and I have never seen the keyholing problem in over 100,000 rounds of cast lead reloads.

I did own a Beretta 92 9mm that would keyhole with lead bullets.
When it happened the bullets would strike the target sideways, making a perfect profile.

What do you mean they are hitting nose first?? Bullets are supposed to hit nose first, keyholing is when they hit sideways because they are tumbling rather than spinning. It means the rifling is not spinning the bullet and stabilizing it so it tumbles.

 

[Walkalong]

Strange. I have shot 1000's of cast lead bullets in 1911's with no leading.

I basically agree with Fred here. I would think the bullets are a bit undersized and the difference in the bores/rifling are making it show up in one gun vs the other. It is, of course, possible the Colt has an undersized bore.

 

[dmftoy1]

+1 on measuring the bullets (if you have any left)

My buddy picked up a colt the same model that you were shooting and the rifling didn't look as sharp to me as on my kimbers so I wouldn't be surprised if .001 or .002 difference in the diameter of your slugs would cause the problem . ..say .451 cast bullets that were actually .450 . . .

FWIW

 

[Kosh75287]

What about bumping the powder charge up about .2 or .4 grains? Do you suppose that the extra "oomph" might be enough to obturate the bullet base in the Colts? Might not be as pleasant to shoot, but might fix the problem. Does this Colt and other pistol do this with jacketed ammunition?

 

[rcmodel]

Real Colt 1911's have pretty shallow rifling because they were designed to shoot FMJ GI ammo.

That being the case, they like hard bullets better then soft bullets when you get up in velocity.

If you notice severe leading in the Colts, the bullets are either too small, too soft, or both.

rcmodel

 

[rodregier]

I had issues with lead projectiles keyholing in 9mmx19. Seating them longer to reduce the jump into the barrel throat (leade) made the problem go away.

 

[DaveInFloweryBranchGA]

To resolve the issue, slug the bore of both pistol barrels and measure the outer diameter of the lead slugs. The one with the closer fit (about two thousandths larger than the bore) will shoot the slugs best. If the bullets are smaller, they'll keyhole.

It's really that easy and what you should be doing when you're shooting lead.

Regards,

Dave