GorillaTactical Posted October 1, 2010 Share Posted October 1, 2010 (edited) I installed a JP Adjustable Gas Block (low profile .750") on my 16" Barrel, Carbine Length gas system AR. I am running a hollow buffer and got a new JP LMOS carrier to go with the Gas Block...After installation, I took the weapon to the range for function testing.....I couldn't get it to cycle anything. With the set screw almost all the way loose, the rifle would barely even eject hotter heavier Match loads, never mind cycle the next round into the chamber...and I couldn't even eject any sort of wolf/steel case. Like i said, the weapon is trying to cycle and ejects the brass, but won't put the next round in the chamber....I took it apart twice and reinstalled the gas system to make sure it was oriented properly etc etc...still the same result.....prior to this, I ran the nonadjustable low profile gas block that came with the upper which had NO problem cycling a heavy spring and heavy buffer with wolf.....any suggestions team? Do I need to give it a break in process? FIXED: ALL HAIL the Enos Forum Problem fixed due to slightly moving the block forward from the shoulder. You guys rock! Now cycles everything including WOLF about four turns out from all the way tight....not to mention that it makes recoil seem barely anything (I can only imagine what a rifle length system feels like haha) Edited October 2, 2010 by GorillaTactical Link to comment Share on other sites More sharing options...
Jesse Tischauser Posted October 1, 2010 Share Posted October 1, 2010 Did u call JP? They have helped me a bunch and never once laughed at my stupid questions. Link to comment Share on other sites More sharing options...
GorillaTactical Posted October 1, 2010 Author Share Posted October 1, 2010 Did u call JP? They have helped me a bunch and never once laughed at my stupid questions. Haven't had time during their hours....will do so tomorrow...just seeing if anyone saw that I was missing something. I'm pretty good at being an idiot when it comes to this stuff Link to comment Share on other sites More sharing options...
MarkCO Posted October 1, 2010 Share Posted October 1, 2010 Other than misalignment, can't think of anything else. No break in required. Was there possibly debris or something else in the actual block ports? Link to comment Share on other sites More sharing options...
GorillaTactical Posted October 1, 2010 Author Share Posted October 1, 2010 Other than misalignment, can't think of anything else. No break in required. Was there possibly debris or something else in the actual block ports? Not a chance...I made sure on the second disassembly that everything was clear....possibly a lighter buffer spring guys? Link to comment Share on other sites More sharing options...
Fullauto_Shooter Posted October 1, 2010 Share Posted October 1, 2010 If I understand correctly, the rifle was running fine with the old gas block, buffer, and bolt. Now it's malfunctioning with the new gas block, hollow buffer, and low-mass bolt/carrier. I'd suggest you identify the problem part(s) using the process of elimination. Try running your old buffer and bolt with the new gas block - if doesn't run, the problem is likely your adj gas block. If it does run, then you've narrowed down the problem to either the hollow buffer or low-mass bolt/carrier. Keep swapping parts out and test-firing until you determine which part (or parts) is causing the problem. My gut tells me the problem may be the low-mass bolt/carrier - have you done a check of the bolt/carrier to see if the bolt moves freely or maybe it moves too freely - problem could be worn or incorrectly installed gas-rings. May also want to check the extractor spring tension. I once had a new bolt that wouldn't run reliably until I replaced the spring. Link to comment Share on other sites More sharing options...
GorillaTactical Posted October 1, 2010 Author Share Posted October 1, 2010 If I understand correctly, the rifle was running fine with the old gas block, buffer, and bolt. Now it's malfunctioning with the new gas block, hollow buffer, and low-mass bolt/carrier. I'd suggest you identify the problem part(s) using the process of elimination. Try running your old buffer and bolt with the new gas block - if doesn't run, the problem is likely your adj gas block. If it does run, then you've narrowed down the problem to either the hollow buffer or low-mass bolt/carrier. Keep swapping parts out and test-firing until you determine which part (or parts) is causing the problem. My gut tells me the problem may be the low-mass bolt/carrier - have you done a check of the bolt/carrier to see if the bolt moves freely or maybe it moves too freely - problem could be worn or incorrectly installed gas-rings. May also want to check the extractor spring tension. I once had a new bolt that wouldn't run reliably until I replaced the spring. Sorry should have clarified....I've run the hollow buffer before. with my old setup. The BOLT is new...but the heavier stock bolt wouldn't cycle either. Link to comment Share on other sites More sharing options...
Braxton1 Posted October 1, 2010 Share Posted October 1, 2010 (edited) When installing the new block, did you push it all the way to the step on the barrel? The JP is designed to be a little forward of that step, since the handguard cap is usually acting as a spacer there. The original gas block/front sight tower will automatically put that space in because of where the tapered pins were originally installed. But also, that new bolt & carrier combination will also require some level of break-in. It all depends on the fit and finish. Edited October 1, 2010 by Braxton1 Link to comment Share on other sites More sharing options...
warpspeed Posted October 1, 2010 Share Posted October 1, 2010 (edited) I'd try the adjustable gas w/ a std BCG and see what happens. The light buffer should not affect it and if the gas is all the way open, it sounds like something is not right with the LMOS BCG. I run a 20" with the same set up and it works with everything. Sorry, slow on the post. Take the barrel and plug one end with a ear plug or something similar. hook a blow gun with compressed air to the other end and with the pressure low, blow air into the barrel. Now, with the gas block loose, move it forward and back like Braxton1 said and find the place where the air flow into through the gas system is the highest and then you will know that the gas block is centered on the hole. Edited October 1, 2010 by warpspeed Link to comment Share on other sites More sharing options...
Doug H. Posted October 1, 2010 Share Posted October 1, 2010 (edited) The gas block is designed to have a gap of about .025" between the back of the block and the shoulder of the barrel. That would be the space where the front metal attach point for a regular handguard would go. You can check to see if the block in in the right place by taking off the comp, closing the bolt and blowing compressed air into the barrel. Keep moving it around until you get the best air flow and that is the spot. I did this the first time I installed an new block, but now I just measure the .025" and it seems to work. If you don't have that space the gas hole will be partially covered. Doug Looks like everyone is typing at the same time! Edited October 1, 2010 by Doug H. Link to comment Share on other sites More sharing options...
calishootr Posted October 1, 2010 Share Posted October 1, 2010 +1 to all before me, you NEED that .25 space, ifthe block is level and the screw is out, that is more than likely the culprit, when i set up mine i used a can of air(keyboard cleaner) and twistedtill i got the most air flow, then locked things down, been working perfect for me so far... Link to comment Share on other sites More sharing options...
GorillaTactical Posted October 1, 2010 Author Share Posted October 1, 2010 (edited) +1 to all before me, you NEED that .25 space, ifthe block is level and the screw is out, that is more than likely the culprit, when i set up mine i used a can of air(keyboard cleaner) and twistedtill i got the most air flow, then locked things down, been working perfect for me so far... Well thanks for the responses thus far...I did this except not quite .25"...that far didn't let any air through...but I moved it about 1/8" forward and the air flow does seems to have increased slightly from where I had it set before. Will take it out to the range tomorrow and come back either thanking yall or crying haha Edited October 1, 2010 by GorillaTactical Link to comment Share on other sites More sharing options...
smokshwn Posted October 1, 2010 Share Posted October 1, 2010 Sounds like youre on the right track, but don't forget to check and make sure that he bcg buffer and spring are providing full travel... Sounds like there may be something that is physically keeping the world from going all the way to the rear. Link to comment Share on other sites More sharing options...
ERIC Posted October 1, 2010 Share Posted October 1, 2010 I think the gas block might not be lined up, rotation wise. It is hard to visually see if low profile gas block is rotated to the right position. Find a flat table and 2 blocks with parallel sides like machinists setup blocks. Take the upper off the lower. Put one block under the gas block (which should be flat) and put the other block under the upper between the take down pins. You should be able to see if the gas block is lined up correctly if both contact points are flat with the blocks. If all the manufacturers did their part, that should line it up. Don’t forget the 0.025” gap but you might want to measure it anyways to confirm it. Link to comment Share on other sites More sharing options...
mpeltier Posted October 1, 2010 Share Posted October 1, 2010 A little trick I use for allighnment of the gas holes is to chamfer the top of the hole on the bbl and remove the set screw in the gas block and use a drill bit that just fits thru it and chamfer the hole in the gas block. The two chamfers allow a slight bit of missalignment to still allow the gas to go thru the system with out obstruction. This should allow the gas block to seat aginst the bbl shoulder and be level, even if there is a slight tolerance issue with one part or the other. Link to comment Share on other sites More sharing options...
Doug H. Posted October 1, 2010 Share Posted October 1, 2010 +1 to all before me, you NEED that .25 space, ifthe block is level and the screw is out, that is more than likely the culprit, when i set up mine i used a can of air(keyboard cleaner) and twistedtill i got the most air flow, then locked things down, been working perfect for me so far... Well thanks for the responses thus far...I did this except not quite .25"...that far didn't let any air through...but I moved it about 1/8" forward and the air flow does seems to have increased slightly from where I had it set before. Will take it out to the range tomorrow and come back either thanking yall or crying haha I think that .25" (1/4") is a typo, should be .025" (1/40" but nobody measures inches that way). Big difference, even 1/8" (.125") is probably too far. Grab a feeler gage to set the gap. Doug Link to comment Share on other sites More sharing options...
GorillaTactical Posted October 1, 2010 Author Share Posted October 1, 2010 +1 to all before me, you NEED that .25 space, ifthe block is level and the screw is out, that is more than likely the culprit, when i set up mine i used a can of air(keyboard cleaner) and twistedtill i got the most air flow, then locked things down, been working perfect for me so far... Well thanks for the responses thus far...I did this except not quite .25"...that far didn't let any air through...but I moved it about 1/8" forward and the air flow does seems to have increased slightly from where I had it set before. Will take it out to the range tomorrow and come back either thanking yall or crying haha I think that .25" (1/4") is a typo, should be .025" (1/40" but nobody measures inches that way). Big difference, even 1/8" (.125") is probably too far. Grab a feeler gage to set the gap. Doug After remeasuring, it was less than an 1/8 of an inch...I have it to where I can physically feel the most air passing through the block. And I have used a set of levels to assure that the block is rotationally aligned correctly with the receiver....thanks for those suggestions And I have made sure that the weapon doesn't have a blockage anywhere else in the action...cycles smooth...just not with the new block Link to comment Share on other sites More sharing options...
TMC Posted October 1, 2010 Share Posted October 1, 2010 Did you replace the gas tube? I just went through a period of cycling problems with my rifle after approx. 5,000 rounds. After trying everything from swaping carriers, bolts and buffers and to new gas rings on the bolt it turned out to be the gas tube. At the carrier end of the gas tube it has a small set-up where the dia. is slightly larger. Well the old gas tube was slightly miss-aligned and the carrier wore down that small set-up which must have allowed too much gas to bleed off. New gas tube and its 100%. Who knew.. Link to comment Share on other sites More sharing options...
TruePunisher Posted October 1, 2010 Share Posted October 1, 2010 Did you put loctite on the adjustment screw and let the loctite set-up before you went shooting? If the adjustment screw is loose you would not get a tight seal and the gas will run out the hole for the adjustment screw. If you put loctite on the screw, but didn't let it set-up then you blew all the loctite out with the fist shot. Link to comment Share on other sites More sharing options...
GorillaTactical Posted October 1, 2010 Author Share Posted October 1, 2010 (edited) Did you replace the gas tube? I just went through a period of cycling problems with my rifle after approx. 5,000 rounds. After trying everything from swaping carriers, bolts and buffers and to new gas rings on the bolt it turned out to be the gas tube. At the carrier end of the gas tube it has a small set-up where the dia. is slightly larger. Well the old gas tube was slightly miss-aligned and the carrier wore down that small set-up which must have allowed too much gas to bleed off. New gas tube and its 100%. Who knew.. I tried a new gas tube...also check it for any obstructions. Did you put loctite on the adjustment screw and let the loctite set-up before you went shooting? If the adjustment screw is loose you would not get a tight seal and the gas will run out the hole for the adjustment screw. If you put loctite on the screw, but didn't let it set-up then you blew all the loctite out with the fist shot. As per JP's instruction, loctite isn't neccesary Edited October 1, 2010 by GorillaTactical Link to comment Share on other sites More sharing options...
TruePunisher Posted October 1, 2010 Share Posted October 1, 2010 Did you put loctite on the adjustment screw and let the loctite set-up before you went shooting? If the adjustment screw is loose you would not get a tight seal and the gas will run out the hole for the adjustment screw. If you put loctite on the screw, but didn't let it set-up then you blew all the loctite out with the fist shot. As per JP's instruction, loctite isn't neccesary Do what you wish as I was only making a suggestion, but if gas is leaking from the adjustment screw you will not get the gun/gas block to function to its full capability. As a side note, I know from talking to people that build the JP rifles, all JP gas blocks on their rifles have loctied adjustment screws. Link to comment Share on other sites More sharing options...
Dan Sierpina Posted October 1, 2010 Share Posted October 1, 2010 I'd use Loctite not to prevent gas leakage, but, to prevent adjustment screw loss! Link to comment Share on other sites More sharing options...
benny hill Posted October 1, 2010 Share Posted October 1, 2010 Don't know cause I never run a carbine lenght gas system but heard you cannot get a light weight carrier & buffer to run in a short gun. You ar'nt running a rifle buffer in a collapsable stock are you? Link to comment Share on other sites More sharing options...
GorillaTactical Posted October 2, 2010 Author Share Posted October 2, 2010 Don't know cause I never run a carbine lenght gas system but heard you cannot get a light weight carrier & buffer to run in a short gun. You ar'nt running a rifle buffer in a collapsable stock are you? I've been known to do some VERY DUMB THINGS....but not that dumb ALL HAIL the Enos Forum Problem fixed due to slightly moving the block forward from the shoulder. You guys rock! Link to comment Share on other sites More sharing options...
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