1,00 rounds on AR15

[Zirk208]

If you want your guns to last forever, don't shoot them.

[Thrasos]

Throat erosion should be minimal at 1k round of modern non-corrosive ammo and a quality barrel. I guess you could check it with a scope or with a bore gauge, but if you're routinely doing drills and/or shooting at 50 meter targets then I doubt you would see wonky groupings. For longer distance/precision shooting (300+ meters), you'd probably would. What barrel is it?