While it's not exactly what you are asking about, what about a LaRue gas block?



It has a nice round shoulder on the front.
If you are having the can made specifically for your barrel, it should not be a problem to fit it to a LaRue gas block.
There is also a 0.875" version.
If your barrel is a 0.940" diameter bull profile, I could re-profile the front end to fit the 0.875" gas block.

Quoted: I might be interested in that.

Shop Services

$50 to partially re-profile a barrel.
$35 more if it's chromoly and needs to be re-parkerized.

Sounds like you need an armalite.
Their picatinny gas block has a small shoulder on the front that might work for you.
There might be room to turn down some of the gas block and make a better shoulder.
Short of that, why not thread the barrel right in front of the gas block and fit a sleeve to locate the can?
How about re-profiling a 0.936" barrel and leaving an 0.875" step in front before stepping down smaller towards the muzzle.
Then have the can made with a mating recess.
Heck, the barrel could even have a tapered seat to seal against like this one I did:



Think outside the box.
We are talking custom here.
I can do anything within the constraints of the barrel size you start with.

Quoted: Quoted: that is very nice Randall. +1. Very nice work indeed.

You mean like this old thing:



JP Rifle handguard covers the junction to the can.
Hand-made adjustable gas tube.
YHM specter gas block allows the big flange for the can.
I never got to see it with the Troy can on it though...