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Posted: 1/12/2009 7:53:02 PM EDT
| I'm not sure which gas block I want yet, maybe PRI, LaRue, Vltor, maybe even a lesser cost unit like Troy. But how do you know if the hole in the block is lined up perfectly with the port in the bbl? I have a Rainier SPR 18" rifle length with one dimple on bottom. Should I make another dimple for the second set screw any of these might have? How best can this be done with hand tools and a dremel? Will the one dimple be exactly where the holes meet up? It seems like there could be a lot of variance in where set holes are between makers.....Any opinions on the PRI adjustable block? |
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I asked a similar question a couple of weeks ago. You will find that the gas block port is typically oversized to allow a little "play" in the alignment with the barrel gas port. My understanding is that most barrels with the single dimple have the dimple lined up with the back side of the gas port. You can do a quick test by plugging one end of the barrel with your hand and blowing in the other end and verifying that you are getting full air flow through the gas block (rotate clockwise and counter-clockwise to feel the difference). Once you get it all lined up you can use a punch or nail to mark the center of the other set screw. You can then drill a small dimple with a drill (the punch mark helps keep the drill bit from dancing all over the place).
I have used Vltor gas blocks but I would imagine that the other available models work well too (I was just geeking out and thought I would have a matching bead-blasted stainless gas block to go with the barrel). If you are really worried about it Rainier Arms might have the gas block dimpler tool back in stock again. It's pretty easy...have fun! |
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Here is how I install my gas blocks. There are certainly better ways but mine works and it works well.
Put the gas block on and align it visually. Once it looks straight it probably is. Tighten the screws down. Take it out to the back yard, range or wherever you can and fire a magazine loaded with various ammunition through it. I use a 30 round magazine loaded with everything from Wolf to TAP. If the weapon function properly the gas block is installed correctly. Take it back home and remove ONE screw from the gas block. Use a drill press and vise and drill an indent into the barrel where that screw fits, be sure to mark your depth so you don't go too deep and pay CLOSE attention not to hit the threads in the gas block. Reinstall that screw with loctite. Remove the 2nd screw. Use a drill press and vise and drill an indent into the barrel where that screw fits, be sure to mark your depth so you don't go too deep and pay CLOSE attention not to hit the threads in the gas block. Reinstall that screw with loctite. You gas block is installed. I have only used PRI and LaRue gas blocks and will continue to use them. |
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