I had a barrel-less RPK kit that was collecting dust.
I ordered an M76 barrel from Apex arms and a 4-pack of MG13 mags
from IMA. AI also got an extended RPK (Yugo-type) receiver from
Coldsteel solutions. 29 cm long.
These parts set around for months until Jan. 1st I began to tinker.
I learned that the longer mag creates an obstacle, and the hammer cannot
reach the short 7.62x39 bolt. The bolt had to be extended along with the
bolt carrier. Bolt carrier was extended by welding on an extension of
scrap metal and milling to shape.
I patterned the bolt mods after the M76 bolt. M76 is on the right.
After I milled out the face, the dimensions are the same.
I used a #8 bushing from Victor Machine to extend the bolt shaft.
These are welding and milling mods.
Another problem. The longer receiver makes the top cover too short.
I took the front section from a spare cover and welded it onto the original.
I use a mig with gas. It takes some practice.
Next. The recoil assembly is now too short to provide the correct action.
Instead of trying to lengthen the spring. I welded a stub to the back of
the piston to compensate. I also had to add 3/8" to the gas piston itself.
I had to weld sleeves on each end of the gas block to get correct fit
on the M76 barrel. I used spare pieces of the top Hand-guard gas tube cut
into 1/4 segments. The RSB had to be reamed out slightly to fit over the barrel. The front sight block fit OK, but I welded on an FAL flash hider
just because it fit nicely over the unthreaded end of the M76 barrel.
This was a time consuming build. Many details. The mag had to be
modified to fit the AK config. Welding of stubs on each end was necessary.
10 days later from the beginning of project it was completed.
I did test fire it before painting.
Bells and whistles. (I welded on a bayonet lug sideways)
The FCG and center support are all shifted back due to the longer magwell.
I don't know who added the by-line at the bottom of my thread.
Probably the K98 guy.