8mm Ammo Question

[BernieT]

Men,
I was wondering about the 8mm Yugo (Century)and the 150gr Romaian cartridges(AIM)surplus, conforming to the dimension specs,SWAMI?,i know i hosed that one up,,,hahaha, any how, my favorite bolt/barrel combo is out of wack,gauging thank's to tomcats stickie on this., and wondered if one of you had measured for conformance,,,the ammo looks great, and runs great most of the time,however, i occasionally get a stuck spent shell between the charging handle rod, and the bolt face, with the neck of the cartridge pointing down.
Thank you,!
Bernie

[JBaum]

FYI, a stuck shell is often caused by an underpowered cartridge not having enough recoil to cause the bolt to hit the ejector hard enough.

[BernieT]

Actually,i found someting scary when investigating my spent brass, after John said week cartridge, i looked at all my brass,and i found the necks on 4 of them to be the same diameter as the case!!!!!,,,,,,i didnt have the go-no-go's a week ago, but this looks to me to be a Out of Battery Fire,,,,!,,or way over pressure,what are the members opinions?, or could it be a hang fire, slow burn?,,,I ran 150 rounds thru her and this is what i have, i'll try and post a photo of the shells,,,totally round, and of course smashed at the front from ejection.
Thank You!
Bernie

[bmg17a1]

Definitely NOT an out-of-battery ignition as the round successfuly fired although it appears that extraction started when the pressure in the barrel was still a bit high with the result that the case pressure formed. An OTB blows the hell out of the case head with the least damage being minor bending of the barrel door all the way up to blowing the extractor through the bottom of the receiver, blowing open and heavily bending the barrel door and damaging the topcover feed and cover.
Extraction with the pressure still high enough to form the cases is not good, and is an indication that worse could happen. I have your recuperator here for new springs, and I'd suggest not firing the gun until you can use the new springs in the gun.
This kind of an event is a rather remarkable balance between the forces of recoil and lockup, such that the case extracts while pressures are high enough to form it. Of course, this is not as the design is intended to work.

Bob Naess

[tomcatshaas]

Bernie has a FA. He told me he wasn't using the bolt catch "anti-bounce" in his bolt. I think this could be the result of that perhaps? What you think?

TC

[BernieT]

Thank You to Bob,Tomcat and John,,!
I installed the short bolt catch, ignorace can be cured!, also i repaired the ejector door spring, it had came off the receiver frame and was resting comfortably aginst the door, thus i believe my caught cases, were mearly bounced back up in between the charging handle and the bolt!,,,I bought a V E R Y nice 8mm barrel from tomcat, installed it, with a new bolt head,checked clearances per tomcats inst. and the gun ran the best it ever did!, John: thank you for the yugo ammo tip on loose bullets, i found several,,,, after firing the 42', 300 rounds, i never had one FTF, or FTE,no dud's, and no pressure formed cases, I even fired 1 complete belt 50 rounds, without letting up,,,it took all of 3 seconds,,,hahahah what a weapon,,,,,,I owe you 3 a HUGE thank You!Bernie

[tomcatshaas]

that's great news Bernie.

[JBaum]

It's a good combination when people give good advice and the guy pays attention. We're all glad to help.

The MG42 does have it's peculiarities, but is easily corrected when it's operation is completely understood.

[noonxnoon]

That is interesting info.

Funny how a single thing that could be overlooked caused an unusual problem.