Suppressed SBR is no longer reliable.

[jerrysimons]

Update: 11/16/2019.

Gun now exclusively shoots PMX XTAC 62gr 5.56 ammo suppressed or not. The LMT-e carrier is awesome, i now have 3 of them. The SLR adjustable gas block works as it should. I believe i had it dialed in within 2 trips to the range.

My setup now has just under 3,500 rounds through it while suppressed with no issues.

Today i decided to see what would happen shooting xm193 unsuppressed....blowing 1-2 primers per mag, short stroking (which i thought was weird).

At the end of today's range session i was pretty determined to buy a different barrel that has a proper gas port. But it runs perfect with 62gr, so ill just buy and shoot that in everything.

I just read this thread for the first time. You have a chamber issue like IraqGunz (blessed be his name) first said was most concerning to him. This is shown because you have effectively fixed the the over gassing issue yet you are still popping primers with a known high pressure ammo 556 ammo. Is this barrel 556 chamber or Noveske Match Mod 0 (that is CHF vs Stainless)? Noveske’s NMM0 chamber is similar to .223 Wylde.
Short stroking is not weird if the chamber is tight, too much friction to pull the case out of the tight chamber which you are now experiencing because you got Noveske’s giant blow hole gas port dialed back with the AdJ gas block and LMT e carrier and it is not driving the bolt back as hard as a result.

[Grip]

Possible, Noveske sucks.

After my update today i have been considering a different brand 13.7 barrel.....

I dunno...

[Pappabear]

13.7 is such a strange length. If you can go shorter and get a a Sionics Reduced gas port barrel or Extreme Reduced Gas port barrel, that might be an option.
I would go there if possible.

PB

RIP IG

[jerrysimons]

Possible, Noveske sucks.

After my update today i have been considering a different brand 13.7 barrel.....

I dunno...

SOLGW make a properly gassed 13.7” midlength. Triarc Systems makes a 13.9” Mid.

But before you buy a new barrel you should eliminate that ammo as a factor. Is it all from the same case/batch? You
Maybe got some overly hot stuff. Buy new/fresh ammo of the same type to eliminate that batch of XM193 as a variable.

[Grip]

SOLGW make a properly gassed 13.7” midlength. Triarc Systems makes a 13.9” Mid.

But before you buy a new barrel you should eliminate that ammo as a factor. Is it all from the same case/batch? You
Maybe got some overly hot stuff. Buy new/fresh ammo of the same type to eliminate that batch of XM193 as a variable.

Its multiple lots acquired in various quantity over the years. I have an LMT mk18 10.5" upper that eats it just fine (using the same magazines).

I have been looking at the SOLGW barrels this afternoon, i may snag one. Do you know the gas port size for those barrels? This Noveske is .086, tuned down with a SLR adj gas block.

[jerrysimons]

Its multiple lots acquired in various quantity over the years. I have an LMT mk18 10.5" upper that eats it just fine (using the same magazines).

I have been looking at the SOLGW barrels this afternoon, i may snag one. Do you know the gas port size for those barrels? This Noveske is .086, tuned down with a SLR adj gas block.

I am interested myself, I’ll see if I can find it.
What type of barrel is your Noveske stainless or chf? One thing to try would be find a armor who has one of Ned Christiansen’s 556 chamber gauges to check it, if it is chf with a marked 556 chamber. If it is Stainless with a Match chamber it will fail the gauge due to shorter throat length spec. Either way I would say if Noveske won’t warranty the barrel one of Ned’s 556 chamber reamers could be the fix.

[Grip]

I am interested myself, I’ll see if I can find it.
What type of barrel is your Noveske stainless or chf? One thing to try would be find a armor who has one of Ned Christiansen’s 556 chamber gauges to check it, if it is chf with a marked 556 chamber. If it is Stainless with a Match chamber it will fail the gauge due to shorter throat length spec. Either way I would say if Noveske won’t warranty the barrel one of Ned’s 556 chamber reamers could be the fix.

It is the stainless 13.7" infidel, 5.56 1:7 twist. I purchased it in 2014, and had marvin pitts at nefarious arms dimple the barrel to shed a little weight....warranty is void.

This barrel was 100% reliable with federal xm193 before a suppressor. When i added the suppressor is when the issue came up due to the massive gas port in the barrel.

Adding the slr gas block and the LMT-E carrier helped a lot, but this gun is tuned for 5.56 62gr and functions 100% on that. The federal 55gr is when the issues come up while suppressed.

I should try tuning the setup to run suppressed on the 55gr and then see what happens with a heavier bullet.

[Clint]

A properly done barrel should not be that sensitive to ammo.

We routinely test with everything from polymer coated Wolf 55gr 223 to 5.56 pressure mil-spec IMI 77gr Mk262, making sure it all cycles and brass comes out in good shape.

Our 14.5" OPTIMUM MPC runs really nicely both suppressed and unsuppressed with a regular mil-spec BCG.

[jerrysimons]

It is the stainless 13.7" infidel, 5.56 1:7 twist. I purchased it in 2014, and had marvin pitts at nefarious arms dimple the barrel to shed a little weight....warranty is void.

This barrel was 100% reliable with federal xm193 before a suppressor. When i added the suppressor is when the issue came up due to the massive gas port in the barrel.

Adding the slr gas block and the LMT-E carrier helped a lot, but this gun is tuned for 5.56 62gr and functions 100% on that. The federal 55gr is when the issues come up while suppressed.

I should try tuning the setup to run suppressed on the 55gr and then see what happens with a heavier bullet.

If it is a 556 chamber I would hit it with Ned’s gauge and reamer guilt free. Problem is finding an armorer that has those and will do it. They are on my list to purchase but I haven’t yet. Otherwise I guess just shoot it with the ammo it works with or buy a new barrel.

[jerrysimons]

If you are popping primers WITHOUT a silencer and it is not just a bad lot of ammo you have a chamber issue, that’s all I know. SOLGW 13.7” mid is 0.078” gas-port for reference.