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Posted: 4/18/2012 7:47:14 AM EDT
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I have a Bushmaster Varmintor with a PINNED gas block.
Can That block be removed and replaced with a Adams Arms piston system without having to switch out the barrel? I know there are piston systems that can use my exiting gas block but are they as good? Thanks! |
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Yes, you can change out your gas block for the Adams Arms kit. See this link for more information. Removing the old gas block starts at around 3:30.
There is also the Osprey 416 piston kit which uses your existing gas block, and has just as good of reviews as the Adams Arms kit. I only have the AA so I can't personally compare them for you. |
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Replacing a pinned gas block with a clamp on will work fine.
The only problem you may have is aesthetics if the new GB does not cover the holes from the old. If you can find a compatible hanguard you like, why not go with the Osprey kit and avoid swapping out the gas block? The Osprey kit has a good reputation. I went with a Magpul MOE drop in handguard, inexpensive, and I really like it. Full floating leaves you fewer options unfortunately. Joe |
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Quoted:
If the origin gas block pins DO go thru the barrel, is that a problem since the AA block does not use pins? Will these un-used holes be an issue? I was thinking about the new AA blocks that are pinned. A clamped gas block, properly torqued will be fine. Old gas block pin holes will not be an issue |
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I recently installed the AA kit on a Palmetto 20" AR upper that had the GI type pinned front sight. The hardest part was getting the pins out of the old sight, they were really pressed in tight and there was only a small rounded pin exposed. I used a press with a punch to press them out. It took 20 minutes of the punch slipping off the pin to do them both. But once you get the pin even started out a tiny bit, they come out with just a few taps. If I were doing it again, I would use a small nail set that had a contoured tip to start the pins out. This would not slip as much as the flat punch I was using. With a better technique, I bet I could do it again in way under 10 minutes.
I have often read of people having to cut the front sight off when they cant get the pins out. Thats the worst case, and I don't think it matters unless you decide to take off the piston and put the old front sight on again. My front block from AA has two screws that tighten and clamp the block in place. I do not think they have ones that have to be pinned in place. I like the piston alot, it has functioned very well for me so far, and I would get this system again. The AA system seems very well made, and a very good design. I also have a similar Bushmaster v-match, and soon I will use the same method to get that gas block off. Not for a piston system, but just to put a railed front gas block on it similar to how my piston upper is now. If you have the time, I'd suggest doing an accuracy test with your old system, and then again after you put the piston on. I started this (the before part), but have not tested it since I put the piston on (the after). |
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I just built a 16" Zombie Killing gun and went with the AA system. Love it, works GREAT! .... Eotech XPS2 (G33STS on order!) light & laser (cheaper version, considering switching to Streamlight TLR 2) Spike Tactical Lower, Mako stock, POF cam.....cant remember rest
I Have two other AR15s.....One is a traditional Vietnam Version (looks wise) except for the front bird cage (thanks New Jersey Laws)......And my Bushmaster Varminter which has a Springfield Armory 6-20x56mm Illuminated green mil dot, 30mm main tube, 1/4" MOA click adjustments...Nicknamed Grim Reaper. The Varminter is the one I'm going to switch to the AA system! As far as left over holes in the barrel, If they are visible once I'm done, is it safe to put something in there to sorta hide them? I will also switch out the cam for a POF version! |
| I've done a handful of installs removing pinned FSB gas blocks. The location of the legs on the AA clamped gas block always covered the pin holes completely. Good luck taking off the FSB. I've had to cut off a couple of them on my installs, because hammering at the taper pins wasn't cutting it. |
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When removing a Bushmaster FSB, drive the pins out from left to right (as viewed from the receiver toward the muzzle)
Use a nail set, Lowes has some good ones. The tip is concave, and will not flatten the end of the pin. Also, get a mini sledge hammer. Like a 2-3 pound head, a standard hammer will not have enough weight to it. Another great tip, if you can, get the entire upper in the freezer for a few hours prior to pin removal. This greatly helps, but rarely possible due to freezer size. |
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