Bolt wear??

[kwando]

I am building a new upper, was using my Go and No-Go gauges today. Using an old BCG that i plan on using with it, it closed on both gauges. Extractor and ejector were both removed.

I put in my <500 round BCM bolt (same without extractor and ejector) and the no-go did not close.

My question is could the bolt really wear that much? That older BCG prob has 2000 rounds through it.

[dwalker460]

Depends on the bolt I would think, probably why they are only about $60 to replace

[Hoser]

Looks like you have a bad bolt.

[BPTactical]

You mention that it will not close on a lower round count bolt. It is possible that the backs of the lugs on the first bolt are worn or out of spec as well. Do you have a micrometer or vernier that you can measure the length of the lugs with?
There is only .003 difference in length between a Go and No Go.

[kwando]

I'll measure tomorrow and post results

[ray1970]

Also, if you're using .223 headspace gauges to check a 5.56 chamber, it is not uncommon for the "no-go" gauge to "go". There are actually different headspace tolerances for the 5.56 and the .223.

Slap my pee-pee if I'm wrong, Bert. [Coffee]

[Great-Kazoo]

Field gauge.
I have owned brand new rifles the No-Go closed on all of them (name brand) some "tier1" Not one of them closed on a field gauge.

[kwando]

Ok... took the complete BCG that came out the original factory upper and the Go closes and the no-go does NOT close... so that BCG with the upper is within specs. Just not with the new upper i'm building.