Valmet M-78 7.62x39 not running right

bruh44

Joined: Oct 2002

Posts: 5114

EE: 100% (182)

NC, USA

Posted: 6/29/2017 11:00:26 AM EDT

[Last Edit: bruh44][Edited]

I have a registered M-78 converted to 7.62x39 from 308. It uses a standard AK bolt not the Valmet bolt. I've put thousands of rounds through it with no issues. Lately it's been getting small pieces of brass between the bolt and firing pin. It locks up the pin so it won't run then. Do I need a new bolt? If so I can't just buy one and drop it in right? What needs to be done to fit it correctly? I do have head space gauges.

18B30

Member

Joined: Feb 2001

Posts: 1246

EE: 100% (258)

OH, USA

Posted: 6/29/2017 1:02:40 PM EDT

[#1]

Change ammunition type and see if problem goes away.

bruh44

Joined: Oct 2002

Posts: 5116

EE: 100% (182)

NC, USA

Posted: 6/30/2017 6:46:17 PM EDT

[Last Edit: bruh44][Edited] [#2]

I had been running Wolf through it. Ran some Tula last night. It ran 100%. It may have been just that. Problem is I have two more cases of Wolf. I'm sure I can use them in something else.
Thanks for the tip.

AubrayJ

Joined: Jan 2014

Posts: 444

EE: 0% (0)

OR, USA

Posted: 10/14/2017 2:04:43 PM EDT

[#3]

Where is the brass shavings coming from? Might have a burr that's causing the problem.

AJ

Sign up to continue the discussion

Create a free account to share your thoughts, follow topics, and connect with the AR15.COM community.

Already a member? Sign In

Valmet M-78 7.62x39 not running right

AK Sponsor

Warning

Confirm Action

Valmet M-78 7.62x39 not running right

Sign up to continue the discussion

Valmet M-78 7.62x39 not running right