What should I do with this thing?

[Circle_10]

Or you could hacksaw/dremmel and file/sand the existing gas block in place, and spray a little high-temp paint on it... then you have a pinned gasblock.

I was wondering about set screw gas blocks for the other barrel mostly. I'm leaning toward leaving the midlength barrel alone now, but if I change my mind about the midlength I'd definitely still opt to just cut the FSB down instead of replace it.

Have you tried other ammo with it? Other match offerings may get you better results.

I've tried a few different loads in it. Oddly, despite the 1/7 twist the gun has shown what seems to be a slight preference for lighter loadings. Prvi M193 consistently shot better through it than Prvi "Match" 69gr, and it seemed to like 55gr Hornady VMax as well. Winchester Ranger 55gr SP shot pretty well too.
I decided to give the IMI 77gr a try because I wanted something that would hypothetically buck the wind a bit more. I've since seen that Magtech 77gr Match seems to be a bit cheaper on average than the IMI and I may give that a try too, but currently the gun is zeroed for the IMI and It's what I keep on hand for the gun.