This is a 20" Oly Stainless Steel Ultra Match Barrel. I built a target upper with this rifle, and put about 100 rounds or so through it. At the time I had 3 20" rifles, so I kinda lost interest in this when it didn't shoot 1/2" out of the box lol. Twist is 1:10.
I've since taken this barrel off, and put 16" barrels on all but one of my rifles, so this is just sitting in a tube by my workbench. Here are the official specs:
"SPECS: 4160 stainless steel, blued, matte finish. 16" (40cm) .980" (24mm) diameter under the handguards, .750" (19mm) ahead of the front sight. Available Post-Ban with crowned muzzle only. A circumferential groove helps secure non-threaded, post ban comps."
Interestingly, this copy states it's chambered in .223, but the barrel is clearly marked "SUM 5.56", so make of that what you will. I think Brownell's must have screwed up.
Barrel is in very good condition, other than the finish shows a little wear from mounting/unmounting/storing it. No gouges, or anything major. Right now, I don't have the FSB on it, but if you need it, I can include it. Whenever I build an upper from scratch, I use a low profile or flip up sight gas block.
This thing did 1moa with my standard 55gr Nosler BT loads, but I think it wants a sligthly lighter bullet, and I was just too lazy to order some and see what I can get this barrel to do. I have no doubt it's capable of sub moa.
Price is $175 shipped, which really makes the cost of the barrel about $160...these retail for over $300, and dealer price from Brownell's is $240.
Payment by MO/Cashier's Check/Certified Check. No trades right now, I need $$ for pimping out my DPMS .308
Pix on request.