"F" marked sight tower

[ca_fireman19]

Ah, I misunderstood...

[citizensoldier16]

My BM came with an A3 receiver and did not have the F marked FSB. After removing the carry handle and installing my ARMS #40, it consistantly shot high even after I backed the front sight out almost all the way.

I called them out on it with a phone call to their service department. After talking to their head gunsmith for about 1 minute, he told me that he would arrange to send me one of their taller front sight posts free. I had it in my hands in 3 days and swapped it out.

[matt86]

what kind of upper do you have?

[ca_fireman19]

I'm not sure about the upper...I was told it was off of a Colt, but the only possible forge mark I can find is a singular dot just forward and below the forward assist...here are some pictures of my FSB...the second shows the ONLY marks I can find on it...

[ca_fireman19]

Can anybody identify these marks?

[bkb0000]

i'm thinking that's not a colt upper.. i'm reasonably certain that all colt railed uppers have F marked FSBs. does the barrel have a "C MP" stamp?

one other thing i might as well mention- that sling attachment will melt pretty easily

[ca_fireman19]

The barrel has no marking unless they're under the barrel nut. As for the sling attachment, would it effect accuracy if I tethered the sling to the FSB itself?

[bkb0000]

The barrel has no marking unless they're under the barrel nut. As for the sling attachment, would it effect accuracy if I tethered the sling to the FSB itself?

not really... it IS tied to the FSB itself. what are you saying?

doesn't sound like a colt upper. scotty will be able to tell you for sure, i'm sure. PM him if he doesn't happen upon this thread.

[ca_fireman19]

It's more like tied around the barrel/gas tube...Who is "scotty"?

[bkb0000]

this is an FSB... just so we're clear

the barrel, FSB, and gas tube all get hot enough to melt nylon in a flash

scotty is "scottryan," and he's our resident colt-savant.