Got a little more done tonight -
Made a left inside 'upper' rail (12") and installed it. Tray straddles the INSIDE rails, not the outside ones screwed to the trunnion, since they're too wide for the tray guides
Started fitting the FT
Temporary AK recoil spring to check rail-to-trunnion & rcvr alignment, and then chambering tests. Both of mine took some work before everything would cycle/lock/unlock easily, with the close-tolerance gas tube
It chambered on the first attempt - sure didn't expect that! Got that same light-headed feeling again
No ejector rail made yet - hopefully tomorrow
Camera LCD is broke or it would be more centered
If you're using a standard diameter piston, here is a handy way to de-burr the inside 'step' in your custom gas tube, with a power drill
Gas tube is MUCH tighter seal (mallet fit) than a factory AK tube; had to drill out the back, so the BC snout could slide forward. That creates a smaller diameter 'step' deep inside the tube, and a problem when reassembling. Like threading a needle dozens of times, during the build. You MG47 builders will soon find out what I mean. Smoothing out that step was the key to easy reassembly
PS Got the 'upper' rails temporarily mounted, and ejection port cut out today
Short vid chambering & ejecting
Sweet....looking good Steve!
How did you go about locating the ejection port? Any specific dimensions to follow or is it lick fingr and hold to wind?
(I'm marking my steel as I type and my build begins.....)
Finger / wind technique works real well
Position the front exactly where it is on a regular AK, in relation the to RSB & trunnion. Cartridge is 2.2" long. Don't go back any further than that, for starters, until you begin test feeding & ejecting. Then study how/what path the ejector pushes the casing
Had to enlarge the port higher than what's in the pic above - symetrical to the bottom, so they'd exit
Stop me if this is a dumb question, but with the elimination of the standard charging handle, how is it that the weapon is loaded initially?
Came up with an idea to eliminate the short-stroke lost pressure worries. Shorten the BC snout, then use a standard-length piston to keep the gas pressure sealed, for a longer sealed stroke. AZ Honkey suggested a good shortening technique (same as an HK51/51K) removing a section of BC snout, then re-join it, to keep the original piston threads. Need to cut the cocking handle slot, and get the 'cocking plate' made too
Been on the road all week, but home now - progress pics should be along soon
Starting to take shape
Good shot of the rails. 'Bottom' rails are the top edges of the 1.5" tube. Planning a flush buttplate with guide tubes for the recoil springs
The front will get trimmed even. Barrel is 9"/ OAL 22"
Next comes the BC extension, and locating the feed stud
Burned through the hinge pin shroud :wallbash: so you see some patch up. Hinge pin holes get hardened
The gas tube goes through the rear sight block to keep pressure contained for a longer stroke. Same set-up as my 6 inch shorty, but longer (4.5" stroke) to cycle the belt feed mech. AMD65 piston in a bobbed carrier, to keep the tube ID small / sealed. Will get pics of it later
Got alot of welding to do yet - some will be repair work :pissed: No guarantee this will work, but hoping to be the first on my block with a 7.62x39 beltfed pistol
How are you going to mount your feed cam roller? Is it going to be like you did on your MG47 and does it have to be right on center on a RPD cover? It appears that the the cam does not track quite on the center line of the top cover.