One of my factory assembled bushy uppers (20" govt profile) has a little over 12k rounds through it, still shoots just fine but I was likely going to replace the barrel anyway in the coming months and give the old one to a friend for a chop job. Should I wait until the accuracy really drops off, or go ahead and replace it? When I originally purchased the upper from bushy I went ahead and ordered 2 extra barrels just to have on hand so money isn't really an issue.

Why replace it if you aren't having problems?

It isn't the amount of rounds down the pipe, its how they were put down it.  FA, bumpfire, or even CQB drills will do more to a barrel than slow fire ever will.

12K rounds is what i call a "break-in" period.  

Most people replace their barrels when the accuracy is no longer acceptable for their intended purpose.  

I don't think I'll ever change the chrome-lined barrel on my Colt LE6920; I'll leave that one for my grandson (and I'm 26).  

However, if I were a High Master in the NRA highpower game, I'd start ditching the barrel once I notice CONSISTENTLY that  shots that should have been 10s are 9s.   For a Krieger Stainless steel, non-chrome lined barrel that's somewhere between 6000-8000 rounds, I believe.  

A thread titled "Typical Barrel Life/Accuracy Problems" was around recently.  Type in barrel life on the search function.  A fellow from UK had a sectioned 1:9 barrel that had seen no FA use.  It had 5500 rounds on it when it wouldn't shoot 855.  The first 1.5" of the rifling were completely gone.  Good pic.

I shoot mostly FA so would likely not do so well.  OTOH, minute of abandoned car is good enough for shoots.

Sam

Quoted: A thread titled "Typical Barrel Life/Accuracy Problems" was around recently.

www.ar15.com/forums/topic.html?b=3&f=12&t=251035