I seem to be getting a number of keyholes...

Maple Leaf Pilgrim

Maple Leaf Pilgrim

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I have a TRP Operator (a .45 ACP M1911A1)with the full length dust cover. A real beauty of a gun, but I seem to be having something strange happen from time to time...

It seems that every once in awhile, I will fire off a box of factory or commercially reloaded ammo and I bring in the target and find that at least ten percent of the hits are keyholed. If I am not mistaken, this may mean that the rounds are tumbling, or that the target is rolling from the last shockwave when the second round hits (but I doubt that). Could anybody tell me what phenomenon could cause a round to tumble out of a 5" bull barrel? What measures would be appropriate for the phenomenae?

Regards.
 
Maple Leaf Pilgrim said:
I have a TRP Operator (a .45 ACP M1911A1)with the full length dust cover. A real beauty of a gun, but I seem to be having something strange happen from time to time...

It seems that every once in awhile, I will fire off a box of factory or commercially reloaded ammo and I bring in the target and find that at least ten percent of the hits are keyholed. If I am not mistaken, this may mean that the rounds are tumbling, or that the target is rolling from the last shockwave when the second round hits (but I doubt that). Could anybody tell me what phenomenon could cause a round to tumble out of a 5" bull barrel? What measures would be appropriate for the phenomenae?

Regards.
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First you have to determine if it is tumbling, most unlikely. Is the ammo roundnose, or ?. What's the backstop like? Solid or waving in the breeze? If you're at a range are others around you set up the same way and experiencing the same thing? Have someone with a .45 take a shot at your target and compare.
 
Bullet tumble because of low velocity or an oversized bore or undersized cast bullets. Because it happens with all ammo, I'd guess your barrel is too big. Hammer a cast bullet through it and measure the bullet with a micrometer. That'll tell you if it's too big. Then either replace the barrel of use bullets of a suitable diameter.
 
sunray said:
Bullet tumble because of low velocity or an oversized bore or undersized cast bullets. Because it happens with all ammo, I'd guess your barrel is too big. Hammer a cast bullet through it and measure the bullet with a micrometer. That'll tell you if it's too big. Then either replace the barrel of use bullets of a suitable diameter.
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He said it doesn't happen with every shot though. Start at the beginning and work through every step before doing something drastic.
 
BC Mike said:
First you have to determine if it is tumbling, most unlikely. Is the ammo roundnose, or ?. What's the backstop like? Solid or waving in the breeze? If you're at a range are others around you set up the same way and experiencing the same thing? Have someone with a .45 take a shot at your target and compare.
Click to expand...

The ammo I use is Remington UMC 230 gr. MC (FMJ).

The backstop is usually corrugated plastic board, like what you use for political campaign signs. But often they are pretty shot out when I get to them so there is a lot of open space behind the target with support only on the sides.

The targets are usually "Green man" 25yd. PPC qualifier targets on a hanger with the aforementioned backstop.
 
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sunray said:
Bullet tumble because of low velocity or an oversized bore or undersized cast bullets. Because it happens with all ammo, I'd guess your barrel is too big. Hammer a cast bullet through it and measure the bullet with a micrometer. That'll tell you if it's too big. Then either replace the barrel of use bullets of a suitable diameter.
Click to expand...

This happens with either factory UMC 230gr MC (FMJ) or the commercially reloaded ammo I acquire, also a 230gr FMJ (the only two rounds I have put through her). Since it happens with both rounds, I doubt it is the bullet. The barrel is a 5" stainless bull barrel in .45 ACP. I have also checked the barrel (especially the crown) and have not seen any burrs or other deformities.

Even though they are going oblong on the paper, they tend to be right in the area where I could expect them to be.
 
Slug your barrel to see if it actually is within spec...I'm pretty sure it it & then try backing your paper targets with some bristol board or cardboard and attach that to the corrugated plastic backer. If its shot to hell & the target isn't firmly attached, the target may be shifting slightly at first impact, giving you oblong holes. You can try shooting with a different pistol, if the same thing happens, you know its the shot-to-hell plastic backer.
 
You may want to check your crimp, it may be too much.

Take a factory round and measure the top of the case neck (at the crimp) and then adjust your crimping die to that measurement.
 
Tipping and keyholing are two different things. Tipping (to some degree) is normal with target loads and does not seem to effect accuracy. Are you getting serious keyholing where you can see a clean cut of the square base of the bullet?

I shot lead bullets (when I first got it) out of my Desert Eagle and experienced tipping. The D.E. uses polygon rifling and the bullets were stripping through the rifling. Copper jacketed/plated bullets cleared it up. Since you are using factory ammo (jacketed I assume) then this should not be a cause.
 
I have experienced key holing with a 30-30 before. A bullet keyholes when the bullet is not stabilized. Cause is usually slow speed, rifling or bullet smaller than barrel diameter.

Before you do something with your gun, try some other brand of ammo and/or bullet weight. Investigate the backstop as others have suggested.

Keep us posted.
 
So what you guys are saying makes sense. I will take measures the next time I hit the range with the Operator and see what comes of it.

So another question, with tipping is this the bullet tipping in relation to the paper or the paper tipping in relation to the bullet?

I had never heard of tipping before, to me it was always tumbling or not. :redface:
 
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