I have had some issues. It was short stroking quite a bit even on the new gas setting 4. I was shooting some brand new UAE ammo and thought that might be a contributing factor. I shot a 30 round mag full of Federal red box with only one incident. Could not function on setting 3. I hope to get the kinks worked out. I also found a pierced primer when I cleaned it afterwards. ??? ???
The barell was ordered straight from Robinson. It came with the new gas system and I had to change the piston tip as I was converting from the old gas system on a 16" light barell which performed flawlessly. I have since purchased a AAC can M42000. I have not shot with it yet. Hopfully the can will create more backpressure.
I purchased my 12" SBR XCR directly from RobArm and with over 1000 rounds through it I have never had a problem I didn't create. I even tested an 11" barrel sent to me by RobArm and still did not have a problem I did not create intentionally.
I run my 12" on gas setting 2 using Wolf ammo and it still shoots the spent brass out 10 to 12 feet from the port. No problems here!
I have a bad bolt. It was piercing primers! I contacted Terra and she sent a new bolt out ASAP! I hope that was the problem with not being able to dial it down beyond #4 setting. The hole that the firing pin comes out of is supossed to have a beveled edge. Not 90 degrees like mine.
The shortie barrels can sometimes have a little trouble with a suppressor on. Especially the 11"ers... we recommend that you don't use them on ones that short. As long as it's functioning, I am relieved. Glad the new bolt fixed the problem. :duh:
I would have thought the suppressor would require use of the lower gas settings even on the 11" barrels. I wonder what the pressure data looks like for the xcr with barrel lengths down to 11" w/wo suppresor... Could Alex make gas valves tuned for the 11" sbr's?
I haven't tried my 5.56 barrel that is 11.5" but on my 6.8 SPC 11.5" I am shooting on setting 2 and could probably go down to 1. I probably wont get a can for them until I get back from the desert so I can't try with that anytime soon. I think my buddies XCR is set at 2 for the regular 16" 6.8 SPC barrel. Not sure what is going on that you cant go below 3.