I have a Wilson Combat 18" rifle gas 6.5 Creedmoor barrel.

I HIGHLY suspect it is not an AR15 gas port nor an AR10 gas port, but somewhere in the middle.

I have a JP HP bolt and carrier. The AR15 gas tube is about 3/16" too short. I am concerned the AR10 rifle gas tube will be about 3/16" too long and bottom out in the carrier key.

Where EXACTLY do I measure from and to on the barre? Center of gas port and to where? And what should the gas system length be for AR10 or AR15 rifle length?

I have already wasted about $100 in ammo and can't get the the barrel to run unsuppressed with a wide open gas setting but it is so over-gassed with a can it is ridiculous.

I don't want to chase my tail if the barrel is defective.

Any stats on measuring gas system length on LR308 pattern rifles is much appreciated.

Have you asked Wilson?

WC sells a different tube for their AR10 RLGS.

https://shopwilsoncombat.com/GAS-TUBE-RIFLE-LENGTH-AR-10/productinfo/TR%2DGTR%2D10/

This 15.5” long, extended stainless steel gas tube is what we use in our large bore AR10 builds.  The slightly longer length gives you a better seal with AR10/LR308/SR25 style gas keys for improved reliability and performance.

NOTE: Not compatible with AR15 “rifle length” gas systems.

Stainless steel
15.5” length for improved performance in large caliber AR10/LR308/SR25 style builds

If you read the reviews, one of them mentions using their AR10 rifle length tube and it bottoming out on a JP carrier key because it is too long on their 18" Wilson Combat barrel. This is almost the exact set up I am running. Wilson Combat 18" rifle gas length and JP bolt/carrier.

I am aware of the issues with people running AR15 gas tubes on AR10 length gas systems. I am also aware of the reverse. The problem is I suspect a gas system length 3/16" between the two. I just need hard data to prove or disprove my theory.