MickB Posted June 18, 2011 Share Posted June 18, 2011 (edited) Just put on a low profile adjustable JP gas block on a 20" barrel upper. It's running a standard weight CAR buffer with a Young Super Light carrier (about the same weight as a JP lo mass carrier). It took 4 and one third turns to get it to cycle with PMC Bronze, which ejected to 4 o'clock. Winchester M193 ejected to 2-3 o'clock. JP's instructions say to start two turns out and go half a turn out till the the bolt will hold open on the last round. I'm wondering how many turns other folk's rifles took. Does 4 and a bit turns open sound typical? Mick Edited June 18, 2011 by MickB Link to comment Share on other sites More sharing options...
bobbleeye Posted June 18, 2011 Share Posted June 18, 2011 Mine took 3 1/2 on 16" barrel shooting 25.8 of WC844 Link to comment Share on other sites More sharing options...
warpspeed Posted June 18, 2011 Share Posted June 18, 2011 Are you running a lightened carrier ? A lighted buffer ? Link to comment Share on other sites More sharing options...
3gunpinoy Posted June 18, 2011 Share Posted June 18, 2011 Just put on a low profile adjustable JP gas block on a 20" barrel upper. It took 4 and one third turns to get it to cycle with PMC Bronze, which ejected to 4 o'clock. Winchester M193 ejected to 2-3 o'clock. JP's instructions say to start two turns out and go half a turn out till the the bolt will hold open on the last round. I'm wondering how many turns other folk's rifles took. Does 4 and a bit turns open sound typical? Mick JP recommendations are just starting points. mine i think is 3 turns from close and my other (exactly same config exect for a difference barrel) is 5.5. I think one must find the correct turns for the gun to cycle well. Link to comment Share on other sites More sharing options...
mhearn Posted June 18, 2011 Share Posted June 18, 2011 Young Manufacturing Lightened Bolt. 12.5 inch barrel. Carbine gas. XM 193 and Atlanta Arms 55 grn. 3.75 turns. Link to comment Share on other sites More sharing options...
MickB Posted June 18, 2011 Author Share Posted June 18, 2011 Young Super Light carrier and standard CAR buffer Mick Are you running a lightened carrier ? A lighted buffer ? Link to comment Share on other sites More sharing options...
cajun0007 Posted June 19, 2011 Share Posted June 19, 2011 Just put on a low profile adjustable JP gas block on a 20" barrel upper. It's running a standard weight CAR buffer with a Young Super Light carrier (about the same weight as a JP lo mass carrier). It took 4 and one third turns to get it to cycle with PMC Bronze, which ejected to 4 o'clock. Winchester M193 ejected to 2-3 o'clock. JP's instructions say to start two turns out and go half a turn out till the the bolt will hold open on the last round. I'm wondering how many turns other folk's rifles took. Does 4 and a bit turns open sound typical? Mick I just bought a JP Light Mass carrier and set my adjustable gas block last week. It only took me 1 3/4 turns to get the bolt to stay open on an empty mag. I opened it up to 2 1/4 turns from closed just to give me a little cushion. I have shot about 850 rounds of XM193 this week without a hiccup. Link to comment Share on other sites More sharing options...
djeffers Posted June 19, 2011 Share Posted June 19, 2011 It took 5.5 for me, but I used a starting load to be on the safe side. Link to comment Share on other sites More sharing options...
01 Z06 Posted August 6, 2011 Share Posted August 6, 2011 I had a rifle that I unscrewed the screw all the way out and still did not open the bolt on a empty mag. The gas port hole in the barrel was too small and had to be enlarged. After that it worked great. Link to comment Share on other sites More sharing options...
prreed10 Posted August 6, 2011 Share Posted August 6, 2011 Hand an interesting hiccup in my rifle settup. I set my JP gas block/LMOS Carrier with my softest shooting load. No problems after about 100 rounds. First match with it and it choked. I was using my pmag with the Nordic extension with 47 or so rounds in it. Hadn't cleaned the gun before the match either. Now I need to back off on the screw some more to make sure it will run that mag when it's dirty. Link to comment Share on other sites More sharing options...
cas Posted August 6, 2011 Share Posted August 6, 2011 I learned with my JP block that what I set it at dry wasn't the same as with loctite on it. Apparently the screw to thread match wasn't real tight and was leaking more gas than I thought. Once it was sealed better with loctite it had a bit more gas than I wanted and had to be readjusted. Just something to think about. Link to comment Share on other sites More sharing options...
MickB Posted August 6, 2011 Author Share Posted August 6, 2011 So what about putting some loctite on the screw while removed from the block, letting the loctite dry and then doing the adjustment? Would that be a better way to do it? I'm getting close to setting my gas screw in place... Mick I learned with my JP block that what I set it at dry wasn't the same as with loctite on it. Apparently the screw to thread match wasn't real tight and was leaking more gas than I thought. Once it was sealed better with loctite it had a bit more gas than I wanted and had to be readjusted. Just something to think about. Link to comment Share on other sites More sharing options...
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