[Fed168]

What causes a reload to keyhole into the target? The round in question was a 9mm, 115 FMJ, reloaded on a single stage press. I'm curious to what causes this, and how to fix/ prevent it.

[Cal4D4]

You might look at your crimp or final sizing of the round. Sometimes backing off the taper crimp slightly can improve the problem.

[Mal H]

Keyholing of a bullet is purely physics as related to the stability of the bullet in flight. Where handloading can affect it most is with bullet velocity. Be sure you are using sufficient powder and that the powder is somewhat matched to the caliber and bullet choice. As Cal4D4 said, the crimp can certainly affect velocity. Bullet weight and shape are important also.

I would look at raw velocity first. If it is below a certain threshold, the bullet cannot be stable and will keyhole. What are the loading details you used for your rounds?

[Standing Wolf]

I've found key-holing is often a sign of too light a load in my .357 magnums. I generally load as lightly as I can for the sake of my wrist.

[Delmar]

In short, "More power, Scotty!"

[Steve Smith]

Velocity, shape, length in relation to spin axis, position of the moon. For handgun, try more juice or give up on the bullet.

[winwun]

Very informative. I had never considered any factor beyond a worn bore to cause keyholing.

I also have arthritic joints and must download, but even at 50 yards and the 115 Rem FBJHP over 4 grains of BE in a .357 case, I get almost tack-driving accuracy with no keyholing and very moderate recoil. With the better Win. HBJHP in the same weight, I get better accuracy.

[bdhawk]

twist rate vs. bullet length/weight. try a different bullet. not knowing your twist rate, the bullet could be too long or too short. also like someone else said, it could be a too light of a load, power wise. i have a small 9mm that keyholes 125 gr. but it shoots the 115 grainers just fine. that part of the fun of shooting and reloading. figuring out how to fix problems like this.

[caz223]

9mm is funny like that.
For best results, shoot the lightest (Shortest) bullet that has the most bearing surface (Usually 115 or 125 flat points), and keep it supersonic.
If you have any lead slugs around, approx .356 or so, drive them through the chamber with a wooden dowel, out the end of the barrel, and mike 'em.
If they mike out at .3555 or less, the barrel is prolly ok.
Also, try plated bullets.
They tend to be just a little bigger around, and softer.
They tend to engage the rifling a little better.