A friend of mine picked up an Arisaka type38 carbine in 6.5MM that is nicely customized, but the shell casings are bulged after firing. This is a common issue with Arisakas and most people just live with it.He wants to cut the chamber area off of the barrel and cut a new chamber. Sounds like a money pit to me.

It may have been rechambered to 6.5 x 257 Rbts. Many were as the ammo for the 6.5 Jap was unavailable.

Do a chamber cast to see what it looks like. Simple candle wax is usable for this as no detailed information will be taken such as measurements.

Spray the chamber with silicone, put some cloth in the barrel just beyond the chamber and pour in the melted wax from the chamber end.

After the wax is hard push it out with a rod toward the chamber end .

I found the same issue with multiple Arisaka rifles. The first time I encountered it, I assumed something was wrong, but after a lot of reading through very old articles I found this was a known issue with these rifles. A couple of the old gun writers who experimented with these rifles commented on it.

I use ample lube, and have no issues resizing therm.

I read somewhere that it was a common practice to put a wrap of scotch tape around the cases just ahead of the extractor cut to support the cases such that they would expand equally. I've never owned an Arisaka, so this is one of those "I've heard" rather than a "This is what worked for me" situation.

I had a nice sporter the had been reamed to 6.5x257 Roberts. Alas it would shoot well. These rifles had a strange rifling and only three lands. Send it to Shaw and have them re-barrel it. The get a Timney sporter trigger with a safety.

It's an Arisaka. The first question you ask is "how much good money should I throw after bad?"