This weekend I did my first gas piston replacement. I used a small drill press I got at Harbor Freight to drill out the original rivet. Cheap "jobber" bits worked fine for that part. I used a spring loaded center punch to mark the rivet (easy to find, runs horizontally with the bolt carrier). A 1/8" bit removes the bulk of the rivet. A 3/16" bit takes the head off of the rivet. Then I put the carrier assembly into a padded vise and then punched the rivet out. My basic guide was this page.
http://www.ar15.com/forums/topic.html?b=4&f=51&t=103051
I also used the ak-builder video on YouTube.
[YOUTUBE]S0hnyTzE2cw[/YOUTUBE]
I used an ak-builder gas piston which is hardened stainless steel (comes with a proper rivet). Man, are those things hard too. They don't come pre-drilled for the rivet so you have to do that. A "jobber" bit isn't going to cut it. I went to Lowe's and got what I think are the best bits they carry. It's a Bosch titanium bit and a two pack of 1/8" bits was about $4. I broke one bit and I'm sure I dulled the other. I don't know where I could have gotten a better bit around BR but I would have gladly done that. After finally getting the hole drilled in the piston (using the bolt carrier hole as a guide) I put in the rivet and then used a body hammer and a ball pein hammer in conjunction with the anvil section of my vise to hammer it over. I did not grind the rivet down flush as shown in the video. It doesn't seem to affect the operation but when I get a proper belt sander I'll probably smooth it out. Considering I had never done this before I think it went pretty well. Again, the biggest problem was drilling the hardened stainless piston hole for the rivet.
http://www.ar15.com/forums/topic.html?b=4&f=51&t=103051
I also used the ak-builder video on YouTube.
[YOUTUBE]S0hnyTzE2cw[/YOUTUBE]
I used an ak-builder gas piston which is hardened stainless steel (comes with a proper rivet). Man, are those things hard too. They don't come pre-drilled for the rivet so you have to do that. A "jobber" bit isn't going to cut it. I went to Lowe's and got what I think are the best bits they carry. It's a Bosch titanium bit and a two pack of 1/8" bits was about $4. I broke one bit and I'm sure I dulled the other. I don't know where I could have gotten a better bit around BR but I would have gladly done that. After finally getting the hole drilled in the piston (using the bolt carrier hole as a guide) I put in the rivet and then used a body hammer and a ball pein hammer in conjunction with the anvil section of my vise to hammer it over. I did not grind the rivet down flush as shown in the video. It doesn't seem to affect the operation but when I get a proper belt sander I'll probably smooth it out. Considering I had never done this before I think it went pretty well. Again, the biggest problem was drilling the hardened stainless piston hole for the rivet.
