Casing Bulge

[Flintlock]

Hello , this is my first post here , I was cleaning my 91/30 , to get rid of sticky bolt , and noticed that some spent casings have a very slight bulge a few milimeters from the rim . Should I worry about this?

[WeldonHunter]

Hello , this is my first post here , I was cleaning my 91/30 , to get rid of sticky bolt , and noticed that some spent casings have a very slight bulge a few milimeters from the rim . Should I worry about this?

Split casings with mil-surp ammo are normal from time to time from what I hear but I've never had any bulge at the rim/base. Mine have split near the neck. Did you check the headspace first of all? If not there's a banner at the top of the page, Okie Headspace Guages, with info. about how to get guages to check it. Second I'd be looking at the chamber to see if there's any corroded places along the walls of the chamber. Can you post a picture of one of the bulging cases?

[Junk Yard Dog]

Check that headspace, if it's bad you can correct it with by replacing the bolt head with another, it may take several bolt heads to get it right, acquire extras on gunbroker or evilbay.

[Chumlee Bumsnag]

I got my Okie gauges yesterday and took Mosin carbines to the range today. A bulge at the base says excessive headspace to me. Have you measured the cases and compared to an unfired case? Here's what the gauges look like.

m-44 groups 007.jpg

[entropy]

Pics of the bulged cases would help a lot. Don't shoot it until you check the headspace!

[mogunner]

I looked at some fired cases from my last range trip and they seem to have a slight bulge about 1/8" up from the rim, nothing major, you can see it just looking at it if you know what you're looking for, I haven't thrown a pair of calipers on it to see what the differences are between it and an unfired one. I know my headspace is good on all mine. Could it just be the case expanding a bit to seal against the chamber wall ? This is on Russian surplus 146gr ammo in my instance.

[zeebill]

Sometimes when the armorer was finish reaming the chamber they would pull the reamer out while it was still running at a high enough speed to have it chase itself around the firing chamber walls. This leaves a little track around the chamber and shows as a bulge around the spent casing. It will sometimes also manifest itself as a hard to remove the spent cartridge rifle and sticking bolt problem rifle. Either way the rifle will never be a real extraordinarily accurate rifle because of the excess chamber volume and the tugging that does on the shell when it is fired the bullets tend to wander or maybe even veer and such things. The ideal thing is a tight and unworn chamber but nothing is that perfect on these babies as they were battle rifles.

Sometimes these little tracks in the chamber are visible with a bright bore light, other times they are not. Erosion of the chamber is another story but either way you need to check the head-space. Remember the Mosin has no way to eliminate any pressure from a ruptured cartridge and if it blows back strong enough to knock the bolt out of bolt lock-up and out the rear of the rifle the next thing it hits is your head and so on! Not a pretty sight as you can guess! Good Luck! Bill

[websterz]

I got my Okie gauges yesterday and took Mosin carbines to the range today. A bulge at the base says excessive headspace to me. Have you measured the cases and compared to an unfired case? Here's what the gauges look like.

m-44 groups 007.jpg

Oooohhhh...nice pic of my babies!!

[Rongo]

Either way.... Checking headspace is a must with older bolt guns. Okie gauges are a great investment. Worth every penny.