Almost three years ago I bought a barrel and bolt from AR Build a box gentleman on this site.
Anyway built the rifle and everything seemed fine, mounted a scope sighted it in and got the gas key tuned right. Probably only put at most 40 rounds of Hornady factory ammo through it. Took it out for deer season in 2015. Hadn't touched the rifle since. I only had a low end Nikon scope on it. So I just bought a new scope and went out to sight in the scope today.
8 rounds into the day... A failure to feed. My bolt no longer had any lugs on it. And after a full tear down of the upper, it appears the lug at the 6 o'clock position on the barrel extension is broke off at the top / tip as well.
I've only shot factory Hornady ammo, none of the cases from today were deformed or showed any sign of over pressure. Chamber and bore look fine. So I'm chalking this up to a defective bolt.
Does a Grendel barrel use a standard M4 extension that is used for a 5.56 barrel?
Anyway built the rifle and everything seemed fine, mounted a scope sighted it in and got the gas key tuned right. Probably only put at most 40 rounds of Hornady factory ammo through it. Took it out for deer season in 2015. Hadn't touched the rifle since. I only had a low end Nikon scope on it. So I just bought a new scope and went out to sight in the scope today.
8 rounds into the day... A failure to feed. My bolt no longer had any lugs on it. And after a full tear down of the upper, it appears the lug at the 6 o'clock position on the barrel extension is broke off at the top / tip as well.
I've only shot factory Hornady ammo, none of the cases from today were deformed or showed any sign of over pressure. Chamber and bore look fine. So I'm chalking this up to a defective bolt.
Does a Grendel barrel use a standard M4 extension that is used for a 5.56 barrel?
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