I'm currently in the market for a new barrel. I use my AR primarily for matches and some training. No serious duty use.
I almost exclusively use M855 and M855A1 since I can get those pretty cheap. I shoot approx 2000 rounds/year.

I've been looking at the 18" Mountain and UltraMatch barrels from Rainier Arms. The gun shop guys told med the Ultramatch should last 6k-8k rounds and Mountain at least double.

Shooting mostly cheap ammo is the UltraMatch worth the extra price? What kind of accuracy can I expect from both barrels shooting M855?