.243 AI

[jbailey]

Just looked at some reloads a friend had from one of his friends. .243 AI. formed from .243 Win Lapua cases. One fired formed and reloaded round tried to take the gun apart, pushing brass into the extractor cut etc.
Checking the fired cases I noticed on the neck some weird stuff. About 3/32 from the case mouth there appeared to be a slight wrinkle all the way around the neck. The loaded cases that were not fired looked the same. That 3/32 land measured .271 dia. Behind the wrinkle, towards the shoulder, the case neck was slightly bulged and measured .276/.277. A .243 bullet would not go into the fired case, which I think it should. Load was being developed using H4350 starting at 35 gr and going to 39 gr in .3 increments. Pulling the bullets on the unfired cases show a charge weight of 38.0 gr of H4350 in the 5 cases I had.

That's all the info I have and I've never seen cases that the neck looked like that. Any suggestions on what might be the problem? Obviously some bad loading technique and I'm trying to get all the dies etc to see what is going on but looking for ideas.

Thanks
Jeff

 

[Laurie]

See what his sized cases look like. If they're OK, it has to occur during bullet seating. (He may have the seater die screwed down too far so the crimp shoulder is in hard contact with the case-mouth.)

 

[Bill Norris]

Sometimes with Lapua brass u will need to turn with a slight clean up to work with a .271 neck. I've seen this be the case in the past.

 

[clowdis]

Sounds like the previous owner has partially neck sized the brass. Very common practice.

 

[jbailey]

Sounds like the previous owner has partially neck sized the brass. Very common practice.

Bingo, that was the problem.
Thanks.

 

[500yards]

The main disadvantage to such a cartridge is usually in the area of feeding. A squarer cartridge will be more apt to bind going into the chamber, as the diameter of the shoulder is closer to the diameter of the rear of the chamber. It could also make for harder extraction in warmer temperatures. The Ackley improvements are a neat idea, as far as 'wildcats' go. They make a .22-250 Rem perform like a .220 Swift, or faster.