User Panel
Posted: 3/24/2017 11:25:53 AM EDT
Gents -
I purchased a LaRue PredatAR 7.62 about 18 months ago and love it. I am starting to shoot it suppressed and it is jamming quite often every 2-4 shots....cant make it through a 10 round mag without at least 2 jams. When it jams it will leave the spent shell sticking out the ejection port about halfway while a new round is trying to load into the chamber. The spent brass is very hot, seems hotter than normal to me although I mostly shoot bolt action rifles, and haven’t ever noticed how hot the brass is on any other AR platform I own. I am shooting .308 Hornady Match 168 gr BTHP...…which I consider high quality ammunition. Suppressor is a SilencerCO Harvester. Any thoughts as to what might be causing this? Do you have any suggestions as to fix this? Maybe switch ammo? I have already switched out buffer and buffer spring to the following per LaRue's instructions. H3 heavy buffer weight - 5.44 oz Spring - Sprinco Tactical Springs LLC .308 M4 CARBINE Extension Tube EXTRA POWER Moly-Plated Chrome Silicon BUffer Spring in Hard Tube (Color Coded Orange) gun is awesome and shoots lights out......I just really want it to run suppressed. thanks in advance. |
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[#1]
Quoted:
Gents - I purchased a LaRue PredatAR 7.62 about 18 months ago and love it. I am starting to shoot it suppressed and it is jamming quite often every 2-4 shots....cant make it through a 10 round mag without at least 2 jams. When it jams it will leave the spent shell sticking out the ejection port about halfway while a new round is trying to load into the chamber. The spent brass is very hot, seems hotter than normal to me although I mostly shoot bolt action rifles, and haven’t ever noticed how hot the brass is on any other AR platform I own. I am shooting .308 Hornady Match 168 gr BTHP...…which I consider high quality ammunition. Suppressor is a SilencerCO Harvester. Any thoughts as to what might be causing this? Do you have any suggestions as to fix this? Maybe switch ammo? I have already switched out buffer and buffer spring to the following per LaRue's instructions. H3 heavy buffer weight - 5.44 oz Spring - Sprinco Tactical Springs LLC .308 M4 CARBINE Extension Tube EXTRA POWER Moly-Plated Chrome Silicon BUffer Spring in Hard Tube (Color Coded Orange) gun is awesome and shoots lights out......I just really want it to run suppressed. thanks in advance. View Quote I use the SLR Sentry 7 Set Screw (0.450" spacing) Adjustable Gas Block on my 7.62 tAR. I tried chasing buffers/springs first, but to me the adjustable block makes more sense. YMMV, of course. |
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[#2]
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[#3]
Quoted:
Gents - I purchased a LaRue PredatAR 7.62 about 18 months ago and love it. I am starting to shoot it suppressed and it is jamming quite often every 2-4 shots....cant make it through a 10 round mag without at least 2 jams. When it jams it will leave the spent shell sticking out the ejection port about halfway while a new round is trying to load into the chamber. The spent brass is very hot, seems hotter than normal to me although I mostly shoot bolt action rifles, and haven’t ever noticed how hot the brass is on any other AR platform I own. I am shooting .308 Hornady Match 168 gr BTHP...…which I consider high quality ammunition. Suppressor is a SilencerCO Harvester. Any thoughts as to what might be causing this? Do you have any suggestions as to fix this? Maybe switch ammo? I have already switched out buffer and buffer spring to the following per LaRue's instructions. H3 heavy buffer weight - 5.44 oz Spring - Sprinco Tactical Springs LLC .308 M4 CARBINE Extension Tube EXTRA POWER Moly-Plated Chrome Silicon BUffer Spring in Hard Tube (Color Coded Orange) gun is awesome and shoots lights out......I just really want it to run suppressed. thanks in advance. View Quote My Tobr did something like this, it ended up being the BCG, call the shop man. |
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[#4]
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[#5]
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Good point, it could be a bad ejector spring or extractor. View Quote View All Quotes View All Quotes |
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[#6]
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y'all think so???? it only has a couple boxes down the pipe. View Quote View All Quotes View All Quotes |
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[#7]
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[#8]
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how much of a pain is it to change it out? I'm pretty good with my hands and tools......just don't really want to screw up my $3k rifle! View Quote Just don't crank down too hard on the screws when reinstalling the handguard, they're pretty weaksauce. |
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[#9]
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how much of a pain is it to change it out? I'm pretty good with my hands and tools......just don't really want to screw up my $3k rifle! View Quote 2) Loosen set screws on bottom of LT gas block (may require a little heat to break the thread locker) and remove the gas block/tube assembly 3) Tap the gas tube roll pin out with a roll pin punch and remove the tube from the LT gas block 4) Insert gas tube into the SLR block, align hole, and install new roll pin (a roll pin starter punch is helpful) 5) Slide the gas block/tube assembly back onto the barrel 6) Align set screw holes with the barrel dimples and install set screws with some thread locker 7) Re-install muzzle device 8) Adjust SLR gas setting to recommended starting point 9) Shoot rifle 10) Adjust gas block setting as necessary Not a bad idea to order one of these 2mm ball drivers to make adjustments easier. They are available in several lengths |
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[#10]
I use a Bondhus 2mm ball driver I got off amazon to adjust my SLR gas block.
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[#11]
Personally, I'd call the shop and talk to them first before I started changing stuff out. Especially on a rifle with only a few boxes through it.
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[#12]
Quoted:
I use the SLR Sentry 7 Set Screw (0.450" spacing) Adjustable Gas Block on my 7.62 tAR. I tried chasing buffers/springs first, but to me the adjustable block makes more sense. YMMV, of course. View Quote Same problem in my OBR. LaRue says it was designed around Surefire suppressor. Tried H3 with oranage spring, then went back to the rifle buffer with 4 tungstens/1 steel. S til having issues. Just put a 5th tungsten in (max) but haven't tested. TON of soot in the magazine/brass :-( I think it is way overgassed (with my 7.62 Specwar) and would love an adjustable block.... |
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[#13]
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I thought the PST blocks utilized two gas holes in the barrel, such that aftermarket blocks won't work. Does this one work??? Same problem in my OBR. LaRue says it was designed around Surefire suppressor. Tried H3 with oranage spring, then went back to the rifle buffer with 4 tungstens/1 steel. S til having issues. Just put a 5th tungsten in (max) but haven't tested. TON of soot in the magazine/brass :-( I think it is way overgassed (with my 7.62 Specwar) and would love an adjustable block.... View Quote |
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[#15]
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[#16]
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y'all think so???? it only has a couple boxes down the pipe. View Quote And I believe that the other guns with this issue were fixed the same way. |
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[#17]
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I shot 700 rounds of M80 through mine right away, and it did it the whole time. Then after a "fix" it still did it, so the second fix was a bigger fix, but it DID actually fix my issue. And I believe that the other guns with this issue were fixed the same way. View Quote |
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[#18]
Quoted:
Personally, I'd call the shop and talk to them first before I started changing stuff out. Especially on a rifle with only a few boxes through it. View Quote |
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[#19]
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[#20]
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yeah they said they don't suggest an adjustable gas block......I just bought a heavier buffer and spring from Slash.......it will be a couple weeks before I can get to the ranch to shoot it though....... View Quote |
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[#21]
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[#22]
OP, I don't think anyone has asked yet...where's your brass ejecting when shooting suppressed and when the gun is running fine?
Your PtAR is probably just overgassed with a can on it. Mine is overgassed when suppressed, but have only had what you explain happen once or twice. I do however have brass marks, which have removed small nicks of anodizing down to bare aluminum on the front of my ejection port and on the flange of where the handguard and upper bolt together. Just a guess, but this is probably what's going on with yours too. Being overgassed, the brass is ejecting too far forward instead of just sideways and out, and the buffer is moving too fast, so the new round hangs up on the spent casing that is not getting out of the upper fast enough. Had the same thing happening with a 12" stealth barrelled SBR at first too, plus gas blowback was harsh so I put the SLR adjustable block on there and got it running smooth. This is my plan for the PtAR too when I get around to buying one. |
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[#23]
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[#24]
Quoted:
OP, I don't think anyone has asked yet...where's your brass ejecting when shooting suppressed and when the gun is running fine? Your PtAR is probably just overgassed with a can on it. Mine is overgassed when suppressed, but have only had what you explain happen once or twice. I do however have brass marks, which have removed small nicks of anodizing down to bare aluminum on the front of my ejection port and on the flange of where the handguard and upper bolt together. Just a guess, but this is probably what's going on with yours too. Being overgassed, the brass is ejecting too far forward instead of just sideways and out, and the buffer is moving too fast, so the new round hangs up on the spent casing that is not getting out of the upper fast enough. Had the same thing happening with a 12" stealth barrelled SBR at first too, plus gas blowback was harsh so I put the SLR adjustable block on there and got it running smooth. This is my plan for the PtAR too when I get around to buying one. View Quote |
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[#25]
Quoted:
I use the SLR Sentry 7 Set Screw (0.450" spacing) Adjustable Gas Block on my 7.62 tAR. I tried chasing buffers/springs first, but to me the adjustable block makes more sense. YMMV, of course. View Quote |
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[#26]
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The 7.62 tAR barrel ID is .750"? Larue's low profile gas block shows options for .875" for the AR10. Is this for Stealth barrels? View Quote View All Quotes View All Quotes Quoted:
Quoted:
I use the SLR Sentry 7 Set Screw (0.450" spacing) Adjustable Gas Block on my 7.62 tAR. I tried chasing buffers/springs first, but to me the adjustable block makes more sense. YMMV, of course. |
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[#28]
Also, got the chance to visit my can (Omega 300) for the first time today. 5.56 PredatOBR ran like a champ on the suppressed setting. The first 10 through the barrel with the 7.62 PredatAR seemed to go well, but then the same issues as the OP saw started popping up (FTE/Stovepipe).
So I'm debating on whether to go with the SLR adjustable gas block or go ahead and pick up a 7.62 PredatOBR barrel kit and swap that out to make what should be the equivalent (minus the cerakote) of the FDE Heavy that's coming out tomorrow. |
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[#29]
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2) Loosen set screws on bottom of LT gas block (may require a little heat to break the thread locker) and remove the gas block/tube assembly View Quote A butane lighter usually works fine on red LocTite, but was a no go on my 7.62 PredatAR. So I got a torch from the hardware store and was able to break the outer two set screws with plenty of heat and some elbow grease, but no luck on the middle one. It's destroyed two Allen wrenches. I've ordered a 3/32 socket in hopes of getting more torque on it but don't have a lot of confidence. Any other tips on breaking it loose? |
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[#30]
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this is exactly what is happening........I have ordered a extra heavy buffer and spring from Slash......it will get installed tomorrow night and then i'm off to the ranch for the weekend......we will see what happens. View Quote View All Quotes View All Quotes Quoted:
Quoted:
OP, I don't think anyone has asked yet...where's your brass ejecting when shooting suppressed and when the gun is running fine? Your PtAR is probably just overgassed with a can on it. Mine is overgassed when suppressed, but have only had what you explain happen once or twice. I do however have brass marks, which have removed small nicks of anodizing down to bare aluminum on the front of my ejection port and on the flange of where the handguard and upper bolt together. Just a guess, but this is probably what's going on with yours too. Being overgassed, the brass is ejecting too far forward instead of just sideways and out, and the buffer is moving too fast, so the new round hangs up on the spent casing that is not getting out of the upper fast enough. Had the same thing happening with a 12" stealth barrelled SBR at first too, plus gas blowback was harsh so I put the SLR adjustable block on there and got it running smooth. This is my plan for the PtAR too when I get around to buying one. |
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[#31]
Does your spent brass have a dent where the extractor catches the lip? Or, do you have popped or "blown" primers? If so, your gun is over-gassed. What's happening is the BCG is starting move backwards before the pressure in your barrel decreases. So, the brass is still expanded. An adjustable gas block is the solution. In my opinion, all 7.62 AR platform rifles should use an adjustable gas block to run optimally.
Also, it takes a significant amount of heat to remove the set screws on the gas block. Just keep at it. |
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[#32]
I was finally able to install the SLR 7 adjustable gas block and it seems to have solved the cycling issues when shooting suppressed.
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[#33]
Don't do nuthin fancy just yet. Call the shop first and let them know of your issues.
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