MG 34 semi-auto
This tutorial uses the conversion kit from TNW firearms. They sell a conversion
kit with the bolt and trigger parts as well as the trigger bar that goes in the receiver
for about $180.00.
The bolt parts include the sear collar, sear collar retaining ring, the semi auto
sear and firing pin spring.
The first step is to disassemble the bolt, then grind off the sear lug flush
with the bottom of the bolt carrier.
Next remove the FA sear and weld the opening shut, I used a piece of
crs for a filler. Make sure it doesn't interfere with the firing pin.
Then trim the bolt to an overall length of 4.805" removing the metal from
The firing pin sleeve needs to be shortened to .627" removing the metal
from the rear. Next a groove needs to be cut for the sear ring retaining clip. I
did this in the lathe with a small grinder and a dremel cutoff wheel. The slot is
.040 wide with an id of .417. The front of the slot is .541" back from the front
of the sleeve.
Next the trigger gate needs to be shortened by .160" there are 2 styles of
these, the other has a lever, but both do the same job.
Install the new spring and modified sleeve on the firing pin and install it
into the bolt and lock it in place. This can be a pita.