Cast bullets key holing in 9mm?
by Slow Hand 
, Indiana, Thursday, September 19, 2013, 07:33 (4076 days ago)
I went out shooting last sunday. After shooting some drills with a few different guns, I looked at the target and notice I had some oblong holes and even a few that looked like the bullets were hitting completely sideways! I was shooting at about ten yards. The load was a Lee 125 truncated cone tumble lube cast of air cooled wheel weights over 4.0 gr of Promo. I shot them through a Glock 19, a S&W SD-9, and a 10" barreled semi auto Uzi SBR. It happened 5-10% of the time and it occurred with all three guns. None of the barrels showed excessive leading. Accuracy was pretty bad for all rounds, not just the key holing ones. I have only shot a few of these bullets and they were in a .38 special. They shot fine in those revolvers. Instead of trying a few since this is a new handload, I loaded up all 400 I cast a couple weeks ago! So, I can't measure them unless I pull a bullet, but since they shot well in a .38, I'm sure thy aren't undersized. The tumble libed bullets are usually a hair oversized with their micro grooves.
Any ideas? I hate to dump the remaining loaded rounds, pulling them with my inertial puller would take a long time and there's so little powder to recover, it's hardly worth it! The scary thing is, I shot the first of these through my Uzi with the can attached! I'm glad they stayed straight enough to not cause a baffle strike!
Cast bullets key holing in 9mm?
by Cannon , Thursday, September 19, 2013, 16:18 (4076 days ago) @ Slow Hand
I'd pull one and measure it. Even if they're starting out plenty big, could you be sizing them down in the seating process?
I recall pulling a handful of bullets from some 500 loads a while back. They had measured .511"-.512" before seating, but the pulled bullets were only .507-.508". I blamed it on a sizing die that was sizing the cases too much.
I'll pull one and measure it.
by Slow Hand , Indiana, Thursday, September 19, 2013, 17:54 (4076 days ago) @ Slow Hand
I'm using a Lee FCD, which I suppose could be resizing te loads round down too small. I've always had excellent luck with the fcd's especially in auto loading pistol calibers. Maybe it is the culprit!
Cast bullets key holing in 9mm?
by Cherokee , Medina, Ohio, Thursday, September 19, 2013, 20:00 (4076 days ago) @ Slow Hand
Generally, undersized bullets can keyhole, and give lousy accuracy. You never mentioned what size you were using. Many people find .357 or .358" works best in their gun(s). The fact that they shoot good in your 38 Special may be attritable to the gun, it may have a tight barrel. The Lee FCD is well known for resizing loads with cast bullets; others disagree. I don't use one. You pulled a loaded round and measured the bullet but never said the size or if its the same size you started with. One time I had some keyholing and I uped the load, solved the problem.