View Full Version : Keyholing .... a few questions, please

Jeff Thomas
September 5, 2000, 11:40 AM
First, if you see a hole that is not a clean, round hole in your target, is that obviously keyholing?

And, I gather any rifle or pistol can 'keyhole'. Is it always the fault of the barrel? Can the shooter induce this effect?

Any other suggestions if one has a firearm that keyholes?

Thanks. Regards from AZ

James K
September 5, 2000, 12:31 PM
Hi, Jeff,

Keyholing is when a bullet enters the target sideways or partially sideways and the elongated hole looks like a keyhole, hence the name. Many bullet holes are not clean, but they are round. The only ones that are clean are those made by target bullets (called "wadcutters" because the holes look like those left when cutting wads for reloading shot shells).

Keyholing is the result of bullet instability. At very short range, some bullets are not stable and will keyhole while they will stabilize farther out and leave round holes.

The most common causes of keyholing, though, are worn or no rifling, bullets unsuitable for the rifling twist, wrong size bullet (.32 in a .38 gun), and gun muzzle damage. There is no way I know of that the shooter could cause keyholing or stop it except to make sure none of the above apply. With a good barrel and proper ammunition, no gun should keyhole, though some target pistols with wadcutter bullets will keyhole consistently. Match officials sometimes ban a gun from a match because the keyholing (and bigger hole size) gives the user an unfair advantage.

Some military bullets have been made deliberately unstable so they will keyhole in a human target, making a bigger and more lethal wound.


September 5, 2000, 12:35 PM
<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>First, if you see a hole that is not a clean, round hole in your target, is that obviously keyholing?[/quote]

Not necessarily - could be bullet lube, bullet shape or target material, but if it's very pronounced, it's probably a keyhole.

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>And, I gather any rifle or pistol can 'keyhole'. Is it always the fault of the barrel? Can the shooter induce this effect?[/quote]

It's either the barrel or the ammo or both. I don't think a shooter can induce a keyhole except through poor ammo selection. I've seen keyholes caused by very bad barrels (wouldn't shoot anything worth a crap), bad ammo (bullet OD out of spec) and bad ammo/barrel matches (very long bullets in slow twist barrels).

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Any other suggestions if one has a firearm that keyholes?[/quote]

Make sure you don't have a bullet/twist mis-match. If that looks OK, then check the bullets for size. If that looks OK then have the bore slugged and checked for spec.

Just my opinion


September 5, 2000, 06:11 PM
The shape of the hole is only significant if you are using a target material that doesn't tear. I make copies of targets on my copier, and lots of times the bullets tear a bit, but they're not keyholing. Shoot something like a sheet of thin plastic to see the effect, keyholing should be obvious if it's present.

September 5, 2000, 06:17 PM
I reload for my pistols (.357sig) and powder makes a difference for me. Using 124gr Rainier bullets I keyhole if I load Power Pistol heavy. If I use AA#7 or #9 I can crank them up.

James K
September 5, 2000, 09:51 PM
Hi, guys,

I just watched one of those "true crime" programs on TV. The multiple killer removed the barrel from a revolver to prevent leaving rifling marks. With only the cylinder to guide the bullets, they keyholed in the victims' bodies. This is really the same as the undersize bullet or no rifling situation mentioned earlier.