Determining if new barrel is needed?

[markm]

I ran an old 14.5 bushmaster barrel well over 20k... With a moderate firing schedule, it'll go another 10k no problem.

[BooneGA]

I ran an old 14.5 bushmaster barrel well over 20k... With a moderate firing schedule, it'll go another 10k no problem.

Same here. I had a 1993 Bushmaster 14.5" upper that I bought used. I put almost 10k through it and sent it off to be rebarreled thinking it must have been due. The new barrel didn't shoot as well as the old one, so it was put back on and returned to me. Sold the rifle off and last I checked its still doing well.

Rick

[Junkie]

With the round count it should still be ok.

BCG has some great deals on complete uppers right now, and they come complete with BCG for free. Depending on his preferences, I'd see if I could manage to afford this: http://www.bravocompanyusa.com/BCM-B...-bfh-kmr15.htm or something similar when it comes back in stock.

[Bruce in WV]

1) Buy a spare barrel and bolt head for piece of mind (along with installation tools).
2) Put stuff away.
3) Shoot current barrel till it fails.
Problem Solved.

I appreciate the info on barrel life and suggestions for if/when to replace the factory BM barrel. I 'll save for the BCM Standard 16" M4 (SOCOM) Upper Receiver Group on sale.
Thank you everyone.

[cd228]

Gauging is near useless. Groups at 300m is a sound barometer of barrel life.

Dano,
Are you saying that performance is a more valuable indicator of barrell condition or Are you saying that the Throat will erode before the chamber gauges will register a difference? Or did your point just completely fly over my head?
Thanks

[HD1911]

the Throat can be completely burned out and the Rifle still Group well.

[T2C]

Gauging is near useless. Groups at 300m is a sound barometer of barrel life.

I have to agree with this. Throat erosion and muzzle erosion are not always good indicators of the accuracy potential of a particular barrel. Unless you are shooting high power rifle competition at 600 yards or farther, I would not even bother with throat and muzzle erosion gauges.

If the headspace is safe, a 10 shot group at 300 meters is a good indicator of whether or not a new barrel is warranted on a carbine.

[patrick sweeney]

At our last patrol rifle class, there was an SBR that practically had the erosion gage fall through, and out of the muzzle. It was still dropping 300 meter pop-ups on the RETS course with no problem. Granted, that's no guarantee of MOA accuracy, but it certainly is minute-of-felon accuracy ,and plenty good enough for practice.

That said, the current lull in AR sales is the perfect time to find a top-quality barrel, easy and not-expensive. (quality is never cheap.)

That way, you're set when the barrel does go toes-up. And Murphy;'s Law being what it is, if you don't have a spare, the toe's-up date will be right int he middle of another buying panic.

[markm]

the Throat can be completely burned out and the Rifle still Group well.

I'll 3rd or 4th this. I've had barrels that I could see the erosion in that still shot fine.

I really would NOT re-barrel a Bushmaster. You're better off buying a complete BCM upper with the offerings out there now.

My old bushmaster's A2 sights were garbage. When I dialed up for distance, the POI moved like a windage adjustment. I pissed away a lot of time/ammo figuring out that mess.

[TehLlama]

I
I really would NOT re-barrel a Bushmaster. You're better off buying a complete BCM upper with the offerings out there now.

Yup - for the effort and hassle, have a complete upper already set aside, and once you're no longer happy with the accuracy of your bushmaster complete upper setup at the longest distance you have access to, swap over and relegate the bushy to a training only upper. Unless you've got piles of AR's, the cost of the tools and time/hassle/possibility of getting something wrong rebarrelling, it's simpler to have a completely good upper receiver (and yes, the BCM KMR uppers are such a good deal now it's silly to look elsewhere if that configuration works.).