Posted: 7/9/2016 2:57:21 PM EDT
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I have a PredatOBR that is short stroking, it is ejecting the empties to around about 3:00-4:00. If I run it with my Suppressor on and the gas set around the middle it works great.
I was using GECO, Wolf Gold, XM193 and some 50grn ammo and got about the same results. Currently it has the white spring that came from Larue installed. Other than putting a scope and bipod on it I have made no changes. |
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Originally Posted By kybluegrass78:
I think the middle is the short stroke setting.:) Originally Posted By kybluegrass78:
Originally Posted By sea2summit:
Gas set to the middle? It's on or off bro  I think the middle is the short stroke setting.:) With the gas set all the way to suppressed it wouldn't function 100% I moved it over a little maybe opening all the way open again and it was 100% with my suppressor. However, without the suppressor it was effectively a single shot rifle. |
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Originally Posted By vader17:
With the gas set all the way to suppressed it wouldn't function 100% I moved it over a little maybe opening all the way open again and it was 100% with my suppressor. However, without the suppressor it was effectively a single shot rifle. Originally Posted By vader17:
Originally Posted By kybluegrass78:
Originally Posted By sea2summit:
Gas set to the middle? It's on or off bro I think the middle is the short stroke setting.:) With the gas set all the way to suppressed it wouldn't function 100% I moved it over a little maybe opening all the way open again and it was 100% with my suppressor. However, without the suppressor it was effectively a single shot rifle. I would remove the barrel and put it back on, something isn't right. Possible the gas tube is off center of the BCG? Totally pulling that out of my butt but it's all I can think of as I'm rotating tires on the truck with a heat index of 113 
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"Oh hell, go ahead and cancel, it's likely not about nuttin'."
I'm an advocate of the 3 chainsaw, two tractor, one wife, one God plan.
I'm an advocate of the 3 chainsaw, two tractor, one wife, one God plan.
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Try a lighter buffer if you have one laying around, or a lighter spring. The XM193 should have had enough oomph to make it work right, but keep in mind the 5.56 versions are optimized for 77gr ammo.... Just a thought....
Caveat: I only own a 7.62 TOBR, but I have owned/built several AR-15s in a couple of different calibers and several barrel lengths (Thus far...) |
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Originally Posted By TXHillCountry:
If it's short stroking on suppressed just run unsuppressed setting? Question is, what suppressor, if it doesn't create that much back pressure then unsuppressed is your setting. When the suppressor is on it works fine for the most part. When the suppressor is removed is when I have trouble and the gas block is set to un-suppressed. |
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Originally Posted By LUVONEGOD:
Try a lighter buffer if you have one laying around, or a lighter spring. The XM193 should have had enough oomph to make it work right, but keep in mind the 5.56 versions are optimized for 77gr ammo.... Just a thought.... Caveat: I only own a 7.62 TOBR, but I have owned/built several AR-15s in a couple of different calibers and several barrel lengths (Thus far...) Any idea what weight their buffers are? |
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Originally Posted By vader17:
Any idea what weight their buffers are? Originally Posted By vader17:
Originally Posted By LUVONEGOD:
Try a lighter buffer if you have one laying around, or a lighter spring. The XM193 should have had enough oomph to make it work right, but keep in mind the 5.56 versions are optimized for 77gr ammo.... Just a thought.... Caveat: I only own a 7.62 TOBR, but I have owned/built several AR-15s in a couple of different calibers and several barrel lengths (Thus far...) Any idea what weight their buffers are? Before buying a buffer check to see if the ammo you shoot cycles with the red spring unsuppressed. That will slow things down a bit on the unsuppressed setting with the suppressor, the lighter weight buffer would be harsher on the unsuppressed setting even if you get things to cycle suppressed (unless that's all you shoot). |
| If you have a factory untouched tOBR then it's probably your ammo. Mine shoots just about everything flawless, except Hearters steel case and Wolf steel case. That junk short strokes cause it's underpowered ammo. Buy a box of Federal Gold Metal Match and shoot it. If it works then it's your ammo. |
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Originally Posted By vader17:
Any idea what weight their buffers are? Originally Posted By vader17:
Originally Posted By LUVONEGOD:
Try a lighter buffer if you have one laying around, or a lighter spring. The XM193 should have had enough oomph to make it work right, but keep in mind the 5.56 versions are optimized for 77gr ammo.... Just a thought.... Caveat: I only own a 7.62 TOBR, but I have owned/built several AR-15s in a couple of different calibers and several barrel lengths (Thus far...) Any idea what weight their buffers are? As I mentioned, I only have a 7.62 TOBR, so I don't know what they weigh. I do know there are H-1, H-2, and H-3 buffers for Carbines. A "general" rule for them is the shorter the gas system, the heavier the buffer you want to run. Rifle/mid length = H-1, Carbine length = H-2, Pistol length = H-3.... Different spring pressures are an option as well. you may need to play with that to find what works best with your favorite ammo. My Colt Match Target HBAR II will shoot anything reliably, even the Wolf if I don't shoot too much of it too fast. Then you get the case stuck in the chamber..... If you shoot the FGMM 77gr you should be able to run reliably all the time. I don't know which spring is stiffer, the red or white, but if your weapon came with both, try swapping the spring. Also, there are places on line that will tell you the weight of the different buffers. |
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Originally Posted By LUVONEGOD:
As I mentioned, I only have a 7.62 TOBR, so I don't know what they weigh. I do know there are H-1, H-2, and H-3 buffers for Carbines. A "general" rule for them is the shorter the gas system, the heavier the buffer you want to run. Rifle/mid length = H-1, Carbine length = H-2, Pistol length = H-3.... Different spring pressures are an option as well. you may need to play with that to find what works best with your favorite ammo. My Colt Match Target HBAR II will shoot anything reliably, even the Wolf if I don't shoot too much of it too fast. Then you get the case stuck in the chamber..... If you shoot the FGMM 77gr you should be able to run reliably all the time. I don't know which spring is stiffer, the red or white, but if your weapon came with both, try swapping the spring. Also, there are places on line that will tell you the weight of the different buffers. Originally Posted By LUVONEGOD:
Originally Posted By vader17:
Originally Posted By LUVONEGOD:
Try a lighter buffer if you have one laying around, or a lighter spring. The XM193 should have had enough oomph to make it work right, but keep in mind the 5.56 versions are optimized for 77gr ammo.... Just a thought.... Caveat: I only own a 7.62 TOBR, but I have owned/built several AR-15s in a couple of different calibers and several barrel lengths (Thus far...) Any idea what weight their buffers are? As I mentioned, I only have a 7.62 TOBR, so I don't know what they weigh. I do know there are H-1, H-2, and H-3 buffers for Carbines. A "general" rule for them is the shorter the gas system, the heavier the buffer you want to run. Rifle/mid length = H-1, Carbine length = H-2, Pistol length = H-3.... Different spring pressures are an option as well. you may need to play with that to find what works best with your favorite ammo. My Colt Match Target HBAR II will shoot anything reliably, even the Wolf if I don't shoot too much of it too fast. Then you get the case stuck in the chamber..... If you shoot the FGMM 77gr you should be able to run reliably all the time. I don't know which spring is stiffer, the red or white, but if your weapon came with both, try swapping the spring. Also, there are places on line that will tell you the weight of the different buffers. Red is the stiffer spring. I shoot 223 and use the white. On my rifle without an adjustable gas block I use the red, it'll shoot (normal) 556 loads but will short stroke on some weaker 223 loads -- suppressed everything works. |
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I made it back out to the range to test again with 5 different types of ammo and no suppressor this time around
55 grn M193, 50 grn Federal tipped varmint, PMC bronze 55 grn, PPU 55 grn and my last box of 55grn independence I wanted to get rid of finally I shout 10 rounds out of each box, 5 rounds with a gen2 30rd pmag and 5 rounds with a 20 round Brownells USGI style aluminum mag. For the first round all 10 rounds of each ammo fired perfectly no problems at all. During the second round I decided to load a magazine with 10 rounds. The M193 fired all 10 with no problems, the 50 grn Federal fired all 10 with no problems. With the PMC, PPU and independence I had nothing but trouble. I would either get a jam with the bolt over a round or no round loaded at all and it did this with a variety of magazines. It seems that the easy resolution is to only shoot good ammo or just use my suppressor all the time. While this isn't that big of a deal I don't really like the idea of a rifle that isn't 100% reliable with any type of ammo. Any suggestions? |
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Originally Posted By JesseCJC:
It's extremely well documented that PMC is known to be problematic in LaRue rifles. PMC X-TAC should work fine as it is 5.56 not .223 like their "Bronze" series. Don't be surprised that a custom weapon is picky about ammo. Looks like you will be fine with 5.56 ammo. I understand the desire to have your weapon 100% reliable with anything you want to shoot in it. I converted a CMMG gas piston rig to DI because it was too picky with ammo. Now it runs anything. Your options for 100% reliability may affect your accuracy, though doubtful. An H-1 buffer should take care of your problem, albeit there will be slightly more felt recoil... But to be sure "Borrow" one from a friend first!!!! Only buy one after you know it works!!!! |