XD Talk

XDMinor · 08-14-2008, 07:05 PM

I went to the range today and shot my Xdm for the first time. Love the gun!! Shot 100 rounds without a problem!! BUT.. I noticed something a little different when I switched rounds from WWB to Remington UMC. Both are 180 grains but this is what I got..

If you look at the round impact, they look like little keyholes. Out of 50 rounds, about 20-30 rounds seem to come out like this.

^^^ These are the Remington UMC rounds. The have a different profile from the WWB. Both were FMJ and 180 grains. But for some reason, the UMC's came out like this. Anyone know why? The profile of the bullet maybe?

vvvv These are the WWB FMJ rounds. They look fine compared to the UMC's.

Anyone know why this is? Is it bad? The gun ran perfectly and is by far the most accurate. This might not be anything, I just thought I would share it to everyone and see if anybody had an answer.

bdraughon · 08-14-2008, 07:08 PM

wow, never seen that b4.

JhankG · 08-14-2008, 07:12 PM

It is called "keyholing." Here is the definition:

The behavior of a bullet whose nose and base are not in line with the main trajectory upon impact with a paper target. The twisted bullet creates a distinctive elongated tear in the target. Keyholing is generally not desired, as it indicates an accuracy-inhibiting factor is present that is causing the bullets to not fly straight.

GW45ACP · 08-14-2008, 07:18 PM

It isn't a problem with the gun and it shouldn't be a safety issue.

What can contribute to keyholing is the ratio of bullet weight and/or bearing surface to rifling twist rate and bullet fit to your specific barrel bore. Some bullets also need a little more distance to stablize since the bullet first spins around center of axis while in the barrel and then center of mass after it leaves the muzzle. That is generally more pronounced in rifle rounds more than PDW pistols and is not likely the cause of your specific instance.

I get keyholing when using .451 sized cast lead in my XD45c, but .452 works great. My friends XD40SC handled 165 grain hard cast great, but keyholed on the 180's.

Have you tried 165 grain jacketed bullet rounds yet to compare a third variable?

mvician · 08-14-2008, 07:19 PM

This is what keyholing looks like

What you have are tears as the bullet passed thru the target

GW45ACP · 08-14-2008, 07:26 PM

Quote:

Originally Posted by mvician

This is what keyholing looks like

What you have are tears as the bullet passed thru the target

This is a valid point. XDMinor, you should try backing your targets with a piece of cardboard to see if you are actually getting slight keyholing or if it is simply a tearing of the paper target.

XDMinor · 08-15-2008, 12:06 AM

Quote:

Originally Posted by GW45ACP

It isn't a problem with the gun and it shouldn't be a safety issue.

What can contribute to keyholing is the ratio of bullet weight and/or bearing surface to rifling twist rate and bullet fit to your specific barrel bore. Some bullets also need a little more distance to stablize since the bullet first spins around center of axis while in the barrel and then center of mass after it leaves the muzzle. That is generally more pronounced in rifle rounds more than PDW pistols and is not likely the cause of your specific instance.

I get keyholing when using .451 sized cast lead in my XD45c, but .452 works great. My friends XD40SC handled 165 grain hard cast great, but keyholed on the 180's.

Have you tried 165 grain jacketed bullet rounds yet to compare a third variable?

No I haven't tried a lighter bullet weight. Hmm... Well if it isn't a safety issue, and it seem to group as well as the WWB, I don't I'll have a problem. I'll try to stay away from that ammo, and stick with the WWB. But on the accuracy side, if the bullet were to travel at a futher distance, then I'm assuming the bullet won't be as accurate. Thanks guys for the advice!