The evilest of MG34 problems. Need some help

[flemgunner]

Fellows I am at a loss. I currently am building a semi MG34 and when testing it for the first time (for fitment of all parts) I put the bolt in and it locked and now.... It is stuck and I mean hard stuck. I cant get it to unlock. The charging handle slipped off, pushing on the barrel and pulling on the bolt or giving it a love tap with a mallet does nothing. Same with trying to turn the bolt head to unlock it.

The bolt is semi modded and worked fine in the receiver till I put on the barrel and jacket.

Now here is what I THINK is happening.
I had to shorten the plunger a bit for it to seat properly. I think I may not have shortened it enough and the barrel is stopping from coming back as far as it should. This, in turn, will not allow the bolt to unlock.

Anyone have any thoughts?

[JBaum]

If it went together, it should come apart under the right circumstances. Have you tried a brass rod shoved down the bore until it's against the bolt face, and push/tap that while compressing the recuperator (pressing the barrel as far rearward as possible) to simulate recoil? Soaking the bolt face with oil by letting oil run down the barrel should provide some benefit for lubricating the roller area.

[flemgunner]

Ahh good idea, Ill try that

[Der Alder]

You may have already tried this, but I've had similar experiences with HK's and my semi MG42's...(as in the bolt locked without a charging handle in place) and what I've done that works well is put a towel over a block of wood and with the butt stock removed slam the gun/receiver down backwards onto it and it usually unlocks the bolt just by the weight of the gun impacting the covered wood.

[Abominog]

If you remove the FH and booster you should be able to get the barrel to slide a bit forward. This probably won't fix the problem, but it will rule out interference caused by the barrel or "something" busted or jammed between barrel and bolt head.

[anjongni]

Hi Flem, the charging handle also releases the bolt catch under the lower part of the shroud.
"The bolt catch (#A19) prevents the bolt from pre-mature unlocking, and serves as a catch for the cocking handle". Folke.
Could having the bolt catch engaged be an additional impediment to the release of the bolt? Could it be jammed in and of itself?
You might have to forcibly re-install the charging handle, or manually lift up the bolt catch to aid in releasing the bolt.
Also, the TNW-type semi-MG34 cocks-on-opening against their strong firing-pin spring. The ramps on the two bolt segments push against/slide along each other to effect this. No...it might not be jammed...it's really THAT stiff! Plus, you are turning the bolt rollers against the cams, unscrewing the threads from the barrel, and compressing the recoil spring, etc...all with the cocking handle.
Please let us know how you resolve this. Best of luck....Phil

[messerschmittfan]

Another suggestion would be to remove the pistol grip to see if something is blocking the bolt from going to the rear. I have several TNW MG34's and have not had any problem like this with them. Harry

[flemgunner]

Got it! Rammed the charging handle back on and while pulling, hit the end of the barrel with a mallet hard as hell. Thanx for all the help guys