M44

[DonH]

Yesterday I slugged an M44 at throat, groove just forward of throat and groove at the muzzle. The throat and groove just ahead of the throat measured .315"+ while the groove at the muzzle went .317"+ (?). Is this typical? I doubted my measurements so repeated the mesauring sevearal times.

[Ricochet]

Dunno how typical it is, but anything can happen. I've got an M91/30 that tapers the other way, slightly tighter near the muzzle than at the breech. It's a good shooter.

As for measuring at the muzzle, sticking a caliper in the muzzle and measuring is misleading, due to cleaning rod wear. Drive a slug in an inch or two and push it back out.

If one's got a LOT of cleaning rod wear, it needs counterboring to fix it.

[DonH]

I measured a slug driven into the barrel at the muzzle. Will try it again, driving the slug in farther, and see what I get.

[Ricochet]

It's common to find old milsurps considerably flared at the muzzle from cleaning rods. If that's the case, they often need to be counterbored to shoot. Many of the Russian refurbs come already counterbored.