[ARCHIVED THREAD] - FSB taper pin question

Posted: 7/22/2005 2:59:46 PM EDT

I just got a new barrel (BM 20" 1:7 Govt. woo-hoo!) and was comparing the FSB taper pins to an existing barrel. I was surprised how different the pin placements are. Why are they so difficult to replicate?

Posted: 7/22/2005 3:11:07 PM EDT

[#1]

Quoted:
I just got a new barrel (BM 20" 1:7 Govt. woo-hoo!) and was comparing the FSB taper pins to an existing barrel. I was surprised how different the pin placements are. Why are they so difficult to replicate?

That "nonstandard" is the industry "standard". The barrel and FSB are a unit and are drilled and reamed that way, each pretty much unique to themselves. Since the FSB is a rough piece, it would be very difficult to precisely locate the holes in the same place on all barrels. I don't think the creators/designers had multiple FSB swaps in mind when they designed it.

Posted: 7/23/2005 5:41:42 AM EDT

[#2]

So what happens in the mititary if a FSB gets hosed? Do they replace the whole barrel?

Posted: 7/23/2005 6:27:59 AM EDT

[#3]

Quoted:
So what happens in the mititary if a FSB gets hosed? Do they replace the whole barrel?

Yep. It's no big deal to them. They have trained people that can do it in a half hour. The $300 or so they likely spent on a new barrel is a drop in the bucket to them.

Posted: 7/23/2005 4:32:00 PM EDT

[#4]

Its almost as if theyre using old technology machining methods. If they used good carbide endmills for the holes they would be more consistant. It seems like theyre using drills.

Posted: 7/29/2005 8:25:34 PM EDT

[#5]

they drill then taper ream holes. i've repaired missing FSB on good barrel by getting soft taper pis and driving into barrel with lock-tite, then machine back to standard after lock-tite cures. put on new or differant FSG the drill-ream and pin IT WILL NOT MOVE. i've got a 0.625 bushy barrel right now i need a FSB and i'm sure i'l have do same procedure on it. it's really not hard and tapered pin reamers are cheap.

Posted: 7/29/2005 9:15:10 PM EDT

[#6]

Quoted:
they drill then taper ream holes. i've repaired missing FSB on good barrel by getting soft taper pis and driving into barrel with lock-tite, then machine back to standard after lock-tite cures. put on new or differant FSG the drill-ream and pin IT WILL NOT MOVE. i've got a 0.625 bushy barrel right now i need a FSB and i'm sure i'l have do same procedure on it. it's really not hard and tapered pin reamers are cheap.

It never occured to me to use loctite to keep the FSB in place for drilling. KISS

Thanks for the tip!

[ARCHIVED THREAD] - FSB taper pin question

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[ARCHIVED THREAD] - FSB taper pin question

[ARCHIVED THREAD] - FSB taper pin question