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Greetings all. I've searched the forum AND the web buy have not been successful in finding a step by step guide on exactly HOW one is supposed to check headspace in the MG34. It doesn't seem as intuitive as the MG42 where you can see and feel the rollers lock into the barrel extension.

What I did was place a GO headspace gauge on the bolt face and inserted it into the barrel extension. I turned it in until it stopped and noted by eye where the roller was in relation to the extension lug. Pretty unscientific. Repeated with a NOGO gauge and it stopped shorter of the same position. I don't have a field gauge yet.

Is this a correct or acceptable method? Could someone please educate us all on precisely how this is done? I was quite surprised to see plenty of mention of headsoace here on the board but no procedure to actually do it. Thanks.

Seriously? No one knows how to do this?

Bob, I'm no expert....I have a s/a MG34 blank firing gun that works. There isn't much written about MG34 headspace, I think because of the miracle of interchangeable parts, and:
-It's built into the dimensions machined into the barrel and bolt
-It can't change
-You can't adjust it
The MG34 f/a drops the firing pin latch at a point at which the bolt is still closing into the thread in the barrel. This point isn't precisely determined, but it doesn't matter either.
In the full/auto, I would say that if you strip out your bolt head and close it on a test dummy round in a barrel, the bolt head should engage "most of the threads". The rollers should probably "just" hit the stops on the barrel. Then you'll know you have "enough". Scientific? No......
In the semi-auto TNW system, if the bolt doesn't thread all the way into the barrel, the firing pin release is "shrouded" and it won't fire. I guess that's a safety feature if for some reason your headspace reduces on you.
That said, there are "barrel and bolt" combinations that work together better than others. Test and identify them, then Sharpie-mark them as groups. In the case of the semi-auto, the bolt is unique and costly, so having more than one would be a real luxury. Hope all this helped......Phil