Sionics Extreme Reduced Gas Port Barrel, Range Report

[WS6]

I believe Centurion’s 12.5 is 0.0625


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That's oddly specific. Are you sure it wasn't a typo describing gas block journal of 0.625"? I thought they were 0.065's.

[Jwknutson17]

That's oddly specific. Are you sure it wasn't a typo describing gas block journal of 0.625"? I thought they were 0.065's.

Centurions spec is .0650. I have had one, and only one pin between .0625/.0630. The other 4 I have or have had pin at .0650.

[WS6]

Centurions spec is .0650. I have had one, and only one pin between .0625/.0630. The other 4 I have or have had pin at .0650.

How did that one run without a can *what buffer/ammo/spring/etc?

[BC98]

Centurions spec is .0650. I have had one, and only one pin between .0625/.0630. The other 4 I have or have had pin at .0650.

I can second this. I pin gaged my 12.5" barrel and it was right at .063". Mine ran unsuppressed with a Sprinco Green spring and an A5H4. With that setup it was right on the edge of function, though. As soon as my gas tube started to wear, the gun would not lock back with 5.56 pressure ammo and wouldn't cycle with .223 ammo. I've since backed it off to a BCM rifle spring and an A5H2. Runs perfect, suppressed or unsuppressed.

[Pappabear]

I have pulled my Burris XTR 1-8 off my Reece build and tossed it on the ERGP barrel to test the accuracy. 1 to 2 MOA is acceptable for a SBR HD gun, but will see what it can do. Range report to follow.


PB

[vicious_cb]

Thats odd, Centurion gas ports have always been on the larger side

0.069" for 14.5" Carbine and 0.080" for 16" Mid when I called them.

[WS6]

How do you pin gauge something?
1)the pin freely slides into the oriface, as in, it would literally almost fall in. Nearly zero drag.
2)the pin slides in with some drag, but no pushing is required. You can still spin it with your fingers while fully passed into and beyond the oriface.
3) the pin begins with some force, and you bet you could lightly tap it all the way, but a pinch grip with bare fingers only allows you to push it half the way through the oriface.

[WS6]

I have pulled my Burris XTR 1-8 off my Reece build and tossed it on the ERGP barrel to test the accuracy. 1 to 2 MOA is acceptable for a SBR HD gun, but will see what it can do. Range report to follow.


PB

It would be destructive, but I'd love to see a test done with an H buffer, on a barrel with a small port, enlarging the port 0.001" at a time until the gun outruns a usgi magazine. Then bring the gun back under control by adding heavier buffers successively.

It would be very interesting to note group size variances, if any, due to timing.

[BC98]

Thats odd, Centurion gas ports have always been on the larger side

0.069" for 14.5" Carbine and 0.080" for 16" Mid when I called them.

My only other CA barrel was a 16" midlength and it gaged at .076" when I had it.

[BC98]

How do you pin gauge something?

Not sure about others but I measure by finding the largest pin gage that can be pushed through the gas port using my fingers only. No tapping, hammers, etc. That's how I've done multiple barrels so far.