Joined
·
491 Posts
After posting a reply to Aziator in a different thread about taking an hour to plan and 5 minutes to do it, I decided to take the bull by the horns.
I followed the directions to remove my barrel and took out the operating rod. I have a set of plastic jaw covers for my vice and the bare barrel was easily clamped horizontally. I had previously replaced the stock Flash Hider with a Primary Weapons Systems combination muzzle break and FH which needed a 5/8 wrench to get off. Naturally I couldn't find any of my 5/8" wrenches so I had to make do, carefully, with a small adjustable wrench. Next the gas block - it had a small locking screw holding it in place which was easily loosened with a 5/32 allen wrench. After that it slipped forward with a minimum of twisting and pulling. I had been wondering how to position the new gas block, but the barrel and the gas block were keyed so no mistakes could be made (well, actually I guess you could put it on 180 degrees wrong just based on the key and slot, but the barrel has a dimple where the lock screw contacts it to make it even more obvious). Installing the new gas block was easy since it was also keyed. I did have to apply a little force to get it completely tight against the barrel shoulder and used a little loctite on both the FH and lock screw.
Next up was the new piston head. The old piston was clamped tightly and the head came off with quite a bit of torque required. It did appear to have some sort of locktite on it, so I put some on the new head and screwed it in tightly.
Putting everything back together gave me a little consternation because I had pulled out the gas tube to look at it and discovered that it has the gas holes in a line down the tube. The tube itself has slots which key to the gas block but it could be installed with the holes facing up into the top rail or down into the bottom of the receiver and I didn't notice which way it was oriented when I pulled it out! I installed it with the holes facing downward for now, and put everything back together. A quick function check and I was finished in a little over 10 minutes (at least half of which was spent looking for the 5/8" wrench and agonizing over the gas tube orientation).
All in all it was an easy swap since I had the vice and plastic jaws. It would definitely be a PITA to swap the piston heads if you had the old gas block on your rifle and the new one on a conversion kit. But now I'm set up and waiting for my 7.62x39 conversion kit.
To finish up, anybody want the old gas block as a spare? Also the picture on the RobArms website doesn't show the orientation of the holes in the gas tube - does anybody know which way it's supposed to go, up or down?
I followed the directions to remove my barrel and took out the operating rod. I have a set of plastic jaw covers for my vice and the bare barrel was easily clamped horizontally. I had previously replaced the stock Flash Hider with a Primary Weapons Systems combination muzzle break and FH which needed a 5/8 wrench to get off. Naturally I couldn't find any of my 5/8" wrenches so I had to make do, carefully, with a small adjustable wrench. Next the gas block - it had a small locking screw holding it in place which was easily loosened with a 5/32 allen wrench. After that it slipped forward with a minimum of twisting and pulling. I had been wondering how to position the new gas block, but the barrel and the gas block were keyed so no mistakes could be made (well, actually I guess you could put it on 180 degrees wrong just based on the key and slot, but the barrel has a dimple where the lock screw contacts it to make it even more obvious). Installing the new gas block was easy since it was also keyed. I did have to apply a little force to get it completely tight against the barrel shoulder and used a little loctite on both the FH and lock screw.
Next up was the new piston head. The old piston was clamped tightly and the head came off with quite a bit of torque required. It did appear to have some sort of locktite on it, so I put some on the new head and screwed it in tightly.
Putting everything back together gave me a little consternation because I had pulled out the gas tube to look at it and discovered that it has the gas holes in a line down the tube. The tube itself has slots which key to the gas block but it could be installed with the holes facing up into the top rail or down into the bottom of the receiver and I didn't notice which way it was oriented when I pulled it out! I installed it with the holes facing downward for now, and put everything back together. A quick function check and I was finished in a little over 10 minutes (at least half of which was spent looking for the 5/8" wrench and agonizing over the gas tube orientation).
All in all it was an easy swap since I had the vice and plastic jaws. It would definitely be a PITA to swap the piston heads if you had the old gas block on your rifle and the new one on a conversion kit. But now I'm set up and waiting for my 7.62x39 conversion kit.
To finish up, anybody want the old gas block as a spare? Also the picture on the RobArms website doesn't show the orientation of the holes in the gas tube - does anybody know which way it's supposed to go, up or down?
