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will99 · February 12, 2012, 07:48 PM

DJ, I just had the same problem with 9mm using lead bullets. The puzzle was solved by seating the bullet as long as possible without actually jamming it into the rifling. Remember, this long bullet also has to feed from your mag, so test the first 5 or 6 cartridges in the mag and just thumb them out gently. They should all come out easily. Also use just a little more Win 231, not a self-defense load, but a good stiff one. That way there's no doubt that the bullet will obturate and fill the bore. I bet this clears up the problem. Understand, that if you have seated too deep, the bullet has to jump to reach the rifling. Hot gas passes the bullet at ignition and can take hot lead with it and prevent a good grip on the bullet. The more you shoot, the more lead builds up and the key holing gets even worse. If you shot a lot of rounds that key holed you no doubt had a mess of lead to clean out of the barrel. Get it all out or you will never find accuracy.

February 12, 2012, 07:48 PM	#13
will99 Member Join Date: June 13, 2009 Location: western NC Posts: 44	bullet tumbling DJ, I just had the same problem with 9mm using lead bullets. The puzzle was solved by seating the bullet as long as possible without actually jamming it into the rifling. Remember, this long bullet also has to feed from your mag, so test the first 5 or 6 cartridges in the mag and just thumb them out gently. They should all come out easily. Also use just a little more Win 231, not a self-defense load, but a good stiff one. That way there's no doubt that the bullet will obturate and fill the bore. I bet this clears up the problem. Understand, that if you have seated too deep, the bullet has to jump to reach the rifling. Hot gas passes the bullet at ignition and can take hot lead with it and prevent a good grip on the bullet. The more you shoot, the more lead builds up and the key holing gets even worse. If you shot a lot of rounds that key holed you no doubt had a mess of lead to clean out of the barrel. Get it all out or you will never find accuracy.