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-   -   AR upper maximum useful life? (http://forums.thecmp.org/showthread.php?t=279057)

wfo87 03-22-2021 11:24 AM

AR upper maximum useful life?
 
I was talking to another high power shooter today. He was explaining to me he had over 10,000 rounds on his AR he uses in 100-200 yard reduced matches. Original barrel but on its 3rd bolt. Let's just forget about accuracy for a minute. Is there a number of cycles a upper receiver can take before cracks and stress fractures can happen? A recommended discard round count? At what point do you worry it's going to come apart on you?

Jakeroub 03-22-2021 01:11 PM

What part of the upper is under stress during firing? As far as I know, life is unlimited...

Gewehr43 03-22-2021 01:33 PM

I inspect them as I clean them...……. As Jake points out there is little to no stress on them...………..
One I have is up to about 17,000rds (by my log books).
I'd have to look and see about how many barrels/bolts that is but the receiver has never been the factor in the drop of accuracy.

Don't fix things that aren't broke.

ken792 03-22-2021 01:40 PM

Battlefield Vegas has upper and lower receivers with over 200k
rounds through them. They keep rebarreling uppers and replacing the bolt heads as needed. At the time of initial posting, they hadn’t worn out an upper or lower yet.

“- Some of our M4's have well over 200,000 rounds down range. Barrels have been replaced, gas tubes have been replaced, BCG's have been replaced but what sets it apart from the AK47's is that upper and lower receivers continue to function. AK's get to about the 100,000+ round count and rails on the receiver will start to crack. It's an easy fix with tig welding but they crack. We have yet to lose an upper or lower receiver from cracking.”

https://www.ar15.com/forums/ar-15/Hi...ge/118-677135/

Later on, they report a number upper threads cracking off, in this particular case a Charles Daly upper.

https://www.ar15.com/forums/AR-15/Hi...77135/?page=32

“ We have uppers with more rounds than that now that haven't broken BUT we also have uppers with 30,000+ rounds that broke. I don't think either the high-round count or the low-round count breaking is anything to judge the uppers on. For the most part, 95% of our uppers continue to function flawlessly and ALL brands of upper receivers have suffered from the same fracture.”

https://www.ar15.com/forums/AR-15/Hi...77135/?page=35

wfo87 03-22-2021 06:48 PM

Thanks for the info. This inquiry had nothing to do with accuracy just safety. I just wondered if they start to stress fracture at some point.

Gewehr43 03-23-2021 02:47 PM

Quote:

Originally Posted by wfo87 (Post 2028075)
Thanks for the info. This inquiry had nothing to do with accuracy just safety. I just wondered if they start to stress fracture at some point.

Well it's possible but as the posts have indicated, the Uppers seem to have a long life.....
Likewise the forward assist and rear sight don't have any wear points really.
I did see one with some scratching (supposedly due to M855A1) around the barrel extension but I'm not so sure about that.....


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