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I just finished some AK Builds this weekend. One of the most time consuming and frustrating points was barrel population. Hoping I can get some opinions on my procedure and see if anyone can optimize my method for more speed and efficiency.
Our parts kits came with New US Barrels that had a 90 degree gas port and slots for the lower hand guard retention cap which probably compounded the frustration. I am thankful for the hand guard slots but the gas port made it a pain in the *** to align.
We also 3d printed out a barrel alignment tool, however, we found the tolerances of the FSBs to be very sloppy/loose from unit to unit. Usually we had a couple of mms side to side
I ended up eye balling the final alignment of the FSB with the alignment tool, I'm sure I can adjust impacts with a front sight adjuster.
On an AR15 I usually flip the assembled upper receiver upside down with a carry handle and FSB check alignment on a flat planed surface and usually that's good enough for me to zero the rifle at the range. If it sits flat, I know it's about golden.
But on the AK; I don't know of a similar method other than bore sighting.
Populating procedure:
Assuming gas port is round and hand guard cap are indexed to each other.
-Drew a line down the length of the barrel such that I hit the middle of the locking pin slot and the gas port
-Pressed on RSB
-slipped on hand guard cap
-pressed gas block with relation to the 0 line I made 90% of the way
-installed upper hand guard gas tube and slowly pressed it as I checked with fitment with the upper hand guard gas tube
-removed upper hand guard gas tube
-checked gas port was clear by using a zip tie down gas block; can't check with a drill bit since the gas port was drilled at 90 degrees instead of angled with the gas block
-pressed front sight block on with relation to 0 line, checked alignment with imprecise alignment tool
-used string alignment theory to kind of check my sanity
-again used 0 line and eye balled relationship of front trunnion to RSB - pressed and prayed
-once confident that the trunnion was properly head spaced and aligned, I drilled the barrel for the respective pins
-punched all the pins in and checked a loose fitment to receiver
-satisfied with alignment, I made a score in the barrel where the trunnion and the barrel met and indexing marks, so that I can accurately press the barrel on to the riveted trunnion later on
-then punched out barrel pin
-pressed out trunnion
So I found a way to headspace pretty quickly, I'm sure I'm going to receive some flak but this is what I did, as I was pressing down the barrel assembly into the trunnion, once I got to about 95% of the way complete, I inserted the bolt to see how much play there was on lock up once there was only a few mms left, I loaded the go gauge into the bolt and inserted it into the trunnion and the barrel. I then very very carefully and very slowly continue to press. Gravity kept the bolt locked in place and I obsessively checked lockup until their was 0 movement, I then checked with the no go and was able to make sure that the no go would not lock up
Our parts kits came with New US Barrels that had a 90 degree gas port and slots for the lower hand guard retention cap which probably compounded the frustration. I am thankful for the hand guard slots but the gas port made it a pain in the *** to align.
We also 3d printed out a barrel alignment tool, however, we found the tolerances of the FSBs to be very sloppy/loose from unit to unit. Usually we had a couple of mms side to side
I ended up eye balling the final alignment of the FSB with the alignment tool, I'm sure I can adjust impacts with a front sight adjuster.
On an AR15 I usually flip the assembled upper receiver upside down with a carry handle and FSB check alignment on a flat planed surface and usually that's good enough for me to zero the rifle at the range. If it sits flat, I know it's about golden.
But on the AK; I don't know of a similar method other than bore sighting.
Populating procedure:
Assuming gas port is round and hand guard cap are indexed to each other.
-Drew a line down the length of the barrel such that I hit the middle of the locking pin slot and the gas port
-Pressed on RSB
-slipped on hand guard cap
-pressed gas block with relation to the 0 line I made 90% of the way
-installed upper hand guard gas tube and slowly pressed it as I checked with fitment with the upper hand guard gas tube
-removed upper hand guard gas tube
-checked gas port was clear by using a zip tie down gas block; can't check with a drill bit since the gas port was drilled at 90 degrees instead of angled with the gas block
-pressed front sight block on with relation to 0 line, checked alignment with imprecise alignment tool
-used string alignment theory to kind of check my sanity
-again used 0 line and eye balled relationship of front trunnion to RSB - pressed and prayed
-once confident that the trunnion was properly head spaced and aligned, I drilled the barrel for the respective pins
-punched all the pins in and checked a loose fitment to receiver
-satisfied with alignment, I made a score in the barrel where the trunnion and the barrel met and indexing marks, so that I can accurately press the barrel on to the riveted trunnion later on
-then punched out barrel pin
-pressed out trunnion
So I found a way to headspace pretty quickly, I'm sure I'm going to receive some flak but this is what I did, as I was pressing down the barrel assembly into the trunnion, once I got to about 95% of the way complete, I inserted the bolt to see how much play there was on lock up once there was only a few mms left, I loaded the go gauge into the bolt and inserted it into the trunnion and the barrel. I then very very carefully and very slowly continue to press. Gravity kept the bolt locked in place and I obsessively checked lockup until their was 0 movement, I then checked with the no go and was able to make sure that the no go would not lock up
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