5.56 Pistol build 3
Since the gas port is already drilled the parts will be spaced from that. I
partially pressed on the rear hinge block, put on the lower handguard
retainer then pressed on the gas block. There is a hole in the bottom of
the gas block where the gas port is so I pressed it on until the reference
lines were centered in the hole. I measured the gas tube and pressed the
rear hinge block on with about .015" clearance. Then I checked the gas
tube fit. It fit properly so the next step was to drill the pin hole and press in
the pin. The pin measured .198" and I used a #9 drill that measures .196".
partially pressed on the rear hinge block, put on the lower handguard
retainer then pressed on the gas block. There is a hole in the bottom of
the gas block where the gas port is so I pressed it on until the reference
lines were centered in the hole. I measured the gas tube and pressed the
rear hinge block on with about .015" clearance. Then I checked the gas
tube fit. It fit properly so the next step was to drill the pin hole and press in
the pin. The pin measured .198" and I used a #9 drill that measures .196".
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Next step is to cut the groove for the lower hand guard retainer. I got
the location for the slot and scribed the barrel. I then used drill bits on
another gun to get the diameter of the groove, it is .228 the size of a #1
drill bit. I made a clamp block from some scrap steel and located the spot
for the hole, then clamped it on the barrel. I drilled a smaller pilot hole for
the bigger drill bit to follow and drilled it out.
the location for the slot and scribed the barrel. I then used drill bits on
another gun to get the diameter of the groove, it is .228 the size of a #1
drill bit. I made a clamp block from some scrap steel and located the spot
for the hole, then clamped it on the barrel. I drilled a smaller pilot hole for
the bigger drill bit to follow and drilled it out.
This is the end result, the slot was a little small so I finished it up with
a small round file. The front end is ready to be pressed into the trunnion
and headspaced.
a small round file. The front end is ready to be pressed into the trunnion
and headspaced.
