We have a straight pull bolt action rifle getting ready for exports, but finding barrels without the gas port is impossible.

Is there anything out there that closes these off, something like a ring would be preferable. My search foo is coming up with nothing on this one.

I have thought about flipping gas blocks around. This is just for a single unit for now so we do not want to spend the effort to make something but would like it to be less obvious than a flipped gas block.

I extended the gas system on my 6.5 gasser from rifle to rifle +2”.  I flipped a gas block around.  It works though doesn’t look great.   Attached File

I don't know if this would work, but what popped into my head was to very carefully tap and countersink the port and JB Weld a short screw in there. Or no countersink and just a grub screw. Making sure that nothing protrudes into the bore of course.

On my .500 Phantom I took the gas block from midlength to CAR length.  I tapped the midlength port half way through and used a plug screw to block it off.  Red Lock-Tite and staking the straight screw slot on both sides and that screw is not coming out and since it was bottom tapped only half way through, it cannot go deeper.  It’s been that way for years and is barely noticeable, especially since it’s under the handguard.  

By the way, it’s .925 at the old port (turned down slightly from .936 originally) so with a .510 bore, I have roughly .207 wall thickness so the ⅛” plug screw works out perfectly for me.

If you really want to go cheap and easy, make a steel ring with rounded edges, like a wedding ring, about a half inch wide, with an I.D. about .002 under barrel diameter at the port.  Heat it, slip it on, and a little touch up on the finish and done.  You could even make it look like a barrel band sling swivel attachment, like this. or this.  It would not look like an afterthought then. Plus, the second one already has the correct ID but would likely need to be soft soldered into place.  No need for silver solder.

Not my picture but have done this in a few barrels.
Just thread the gas block gas hole for 10-32 and put a set screw in it.
Mine are vented to shrink the gas port but just put a set screw in and you're good to go.
Attached File

Turn the gasblock around and pull off the gas tube.

That looks like the game plan.

I think I will also pop it on a manual mill and cut it in half as well as mill the gas tube part off.

I did something like this to a barrel that I'm using on a bolt-action AR build.  Only I made a 1" long x 7/8" OD shrink-fit sleeve to fit a .625 gas journal.  It's hidden under the hand guards.  You could also make a plug pin and cross pin it into the gas block instead of a gas tube.

This is what I really wanted to do, but I had to ship the rifle off already. For export rifles, this is what I will do in the future.

Just hoping the flipped gas block works for the compliance in the other country, but thinking about this, I may make a ring and send it along separately.