I did some scary math for my .223 the other day. I've had it 13 years. When I was back up in Sheffield I recon I put at least 50 rnds per week through it ver 5 years. So call it 12000 allowing for holidays etc. I've used it significantly less since moving down here, but I would say conservatively another 3000 rounds in the the last 8 years. It was only about a year ago I decided accuracy was no longer acceptable. It now about 2moa with GGG below 500yds. For some reason (I suspect because it is tearing the jackets up too much) it falls of a cliff at 500.
So 15000 rounds barrel life for a .223.
When I get my AR up and running I'll be taking part in a few CSRs myself.