MG34 Issues

[rgus48]

Earlier this year I send Stan at Project Guns a cut MG34 receiver to rebuild. He sent it back asking me to give him a few months to finish up his last RPD run before I send the full gun for final build. I held off and sent the gun in August. Before he left on vacation this last time he left me a VM that the gun was done and he had to test it and he expected to get it shipped out before he left. Vacation came and went and I didn't hear from him so I called him about a month ago and he told me he was having issues with the gun firing a couple rounds and then not ejecting. He said he needed to work on it to resolve what wwas going on and he would let me know. Stan called me at my office yesterday and told me he has had no luck with a fix n the gun. He says the booster is 400 thousands, about 11.5 mm and he thinks it needs a small booster. He said the bbl ,also matching, seems to be "sloppy" in the booster. He called his supplies and they would sell him a booster but would't check the size. He says the gun is "slick' , the extractor is perfect and he is stumped. He said it has the best trigger of any MG he has ever worked on. He is convinsed it has to be in the front end , booster area, of the gun. He told me he cannot spend any more time on the gun and will ship it back. He said the is the first gun in 6 years that he coundn't get to run right. Lucky me! In all fairness to Stan he only charged me for parts and no labor and he has a TON of time in the gun.
You guys are the best of the best, what do you think?

[messerschmittfan]

I think Stan is right, the problem is in the booster area. That is an easy fix if you have a smaller diameter booster. However before that I would check to be sure the barrel is recoiling like it is suppose to. When ever I had a problem with a MG34 not cycling right I would soak the bolt in a can of oil and let it drip dry for only a couple of minutes before putting it back in the gun and shooting it. It makes a mess but normally if you can make it cycle for a belt or two it will settle itself in. If that does not work then it is definitely the booster. Harry

[Blanksguy]

As the other post to this thread suggested, there are several other things (challanges) that may be in play here.
Some of these are associated with any of the moving-parts slightly "dragging" to any amount during operation......some of these are:
1: Barrel movement in barrel-jacket.
2: Recoperator-rod/spring inside lower-part of receiver not allowing full barrel movement to the rear during operation.
3: Bolt-lock (for lack of correct nomenclature) possibly not fully seated or dragging on bolt-roller as barrel-assembly with locked bolt move to the rear.
4: Ejector-rod dragging on the inside of receiver......or bolt-ejector-rod slightly bent.
5: Other parts of the semi-only firinmg-mechanism dragging on bolt as it moves to the rear.
6: Buffer needing adjustment to a slightly shorter length.
7: Inconsistant ammo loading.....try known good ammo that is not more than a few years old to weed out ammo issues......but remember to keep the ammo at/near the same loading for WWII German ammo.
8: Bent barrel-jacket.
9: bent and/or dragging feed-parts inside the top-cover or a top-cover that is slightly bent downward.
10: Worn barrel-bushing and/or forward area of barrel that has the outside grooves worn......where you lose part of the rearward gas pressure during firing.

These are just a few of the items to check.....there are others and I am sure that several Board-Members will add more.

Remember that anything that feels like it is "dragging" will use up part of the recoil "pulse"......and these need to be corrected.
Anyplace that has worn parts at the muzzle that are acted upon by gas=-pressure need to be checked.....replace worn parts.


Regards, RichardS in Bay City, MI
US Army, Retired
Blanksguy2001@chartermi.net

[rgus48]

Well I finally have the gun back from a real gunsmith and it runs just great. The problem basically was that Stan at Project Gun screwed up the receiver reweld. It looked great from the outside but on the inside the channel that the recoupliator, not sure if that is spelled right, runs in was off just far enough to cause the rod to get in a bind when the barrel recoiled into it. It took a real gunsmith to locate the problem and repair it because Stan couldn't get it to run. My gunsmith, the same one that built my MG42 from an original receiver, didn't have a tool that would get into that area so he hand lapped it until the rod would function properly. He also had to repair the rod. He did tell me that a disk in the bolt was also damaged and recommends that it also be replaced. Now the gun functions as it should and I have to locate this disk he is talking about. Anyone know what part I need to look for?

[www.Prussia.us]

First congrats on getting your '34 working, second sorry about your experience with Stan I sent him work since the beginning and he was always really helpful, third please PM me your gunsmith (never hurts to have the name of a good gunsmith in case needed), ,,,,,,,finally:

try www.BRPguns.com call Brian directly he use to have a bunch of small parts, www.sarcoinc.com Sarco may still have a few parts but it has been a while since they stocked them, there is www.Mg34.com but only as a last resort, also www.marstar.ca, Marstar in Canada, it should not be an issue to import that part I presume.........good luck.

[anjongni]

The "disc" in the bolt sounds like a TNW part unique to the semi-auto system. You might give them a call up in Oregon...Phil

[42rocker]

Glad to hear that you have it up and running. TNW will also (if normal) be at Knob Creek in Oct.

Later 42rocker