www.MG42.us

Hey guys need some help with a gun Im working on.
Straight up MG42 F/A, everything feels fine and looks/feels normal. The issue is its firing fast. Like WAY fast, like 1800 RPM fast. Its nuts!
Ive swapped to the longest stiffest recoil spring I have. Pogo test on the recoup feels normal. IS there a way to check the buffer? I dont have my JBaum manuals handy so Im not sure.
Thoughts?

That's a Texas fast all right 180 rounds per minute. Wow.
If I remember my reading. Speed is also factor of how "Hot" the ammo is. So how "hot" is that ammo.Smoking Hot or what????

More Later when I get another break at work.

Later 42rocker

Did you try a heavy bolt? Are the rollers undersized maybe so premature unlock?

flemgunner,
Lets go back and start at the beginning with a couple questions......which the answers can help us help you.....

1: 8x57mm or 7.62x51mm/.308 (?).......and who manufactured the ammuntion that was used for this firing (?).

2: Booster-Cup/Nozzle hole-size (?).

3: Long or short Barrel-Bearing (?)......measurement in inches please:___________.

4: Original Receiver MG42, or something someone put together/welded together such as a "Post-86" gun (?).

We will also need a couple of clear photos of the gun from the right-side with parts removed and laid out next to gun so that we can see what you have to work with......to include the barrel/recoil-spring/bolt-assembly and buffer-unit......and flash-hider/booster-cup ("Nozzle) and barrel-bearing.

Also need to know if the bolt-head is from a practice-ammo/plastic-ammo set-up (?).........and see a clear photo of the bolt-head.

These may/may not be the only questions and/or requests for clear photos to be able to help you sort this out.
Regards,
RichardS
US Army, RET

The problem is that with using a heavy bolt, which is available to buy, it's supposed to be used with a heavy buffer, which isn't available to buy. Don't use the heavy bolt without the proper buffer, or you'll beat the gun to death, and I don't want to even be near when that happens.

Think I found the problem. While taking it apart for pics and stuff I noticed the barrel bearing looked strange.
Turns out there was an MG3 barrel bearing in it. Made the little expansion chamber kinda huge.
So if you want your 42 to run retarded fast drop one in it.

Yup, that'll do it.

flemgunner,
I would think that the longer Barrel-Bearing (being longer) would hold the pressure inside the Booster-cup/"Nozzle" slightly longer as it moves to the rear attached to the front of the barrel.......and not allowing the excess gas-pressure to escape out the vents in Flash-Hider (?)......and the shorter Barrel-Bearing allowing the earlier escape of gas-pressure out of the vents as the recoiling parts move towards the rear.

Later escape of Gas-Pressure = faster moving parts.
Earlier escape of Gas-Pressure = slower moving parts.

What about my other questions listed above (?).

Regards, RichardS
US Army, RET