ARC issues

[Olderthan dirt]

Loading 338 arc for an ar platform. Started out using 225gr SST super and subsonic. 16” Shaw barrel 1-8 twist pistol gas alien gear adjustable gas block. Loads were all using lilgun. Supers cycled fine, subs were slow (700fps) and cycled without having to adjust gas.
Switched to a 10” barrel .Gas wide open.
Nothing works.
Switched to H110 and 300 gr T-Rex maker bullets.
Subs were going 1090 no cycle but stable.
Added can, still no cycle(25 fps increase)
Next on the list is AA1680 to try tomorrow.
If this doesn’t work the Shaw goes back on.

 

[CCM]

What's the gas port size on the new barrel?

 

[dk17hmr]

Is the gas block lined up properly with the gas port? Is the gas tube plugged?

 

[Olderthan dirt]

I checked the gas tube alignment and the hole is in the center of the circle ( gas ring circle on the barrel ) . The gas tube is not obscured.

 

[Olderthan dirt]

The gas port is smaller
0.069 vs 0.093

 

[Olderthan dirt]

Opened it up with a #43 bit gave me 0.090
Back to the range

 

[CCM]

Opened it up with a #43 bit gave me 0.090
Back to the range

If you're using an adjustable block, I'd go .105-.110.

 

[Olderthan dirt]

CCM is correct.
Got some movement of bolt with gas opened all the way up.
11.5 gr of H110 under 300 gr Trex operated without suppressor.
10.5 would eject but not load another from mag( this was suppressed) but it gave me ONE hole at 25 yards for three rounds 1026 fps SD of 10.
Bigger gas port here I come.