[ARCHIVED THREAD] - (info req) Installing a new FSB

Posted: 9/28/2006 10:54:05 PM EDT

I would like to mount a new FSB with bayonet lug on my AR, can i Use the new one and new pins on my barrel as they are or I have to fit them?

Thanks for any info gents,

Posted: 9/28/2006 11:07:07 PM EDT

[#1]

The FSB is drilled with the barrel. You will need to find a machinist with the proper set up to fit a new FSB. In the US I believe ADCO does it, but I see that you are in Italy.

ETA: You could also look into a screw-secured FSB, or perhaps you will get lucky and the new one will fit.

Posted: 9/28/2006 11:14:19 PM EDT

[#2]

Don't know if you need this info also but here goes just the same:

FALARAK'S BIY HOW TO

Down the page where he installs a FF tube. Shows you how to take off FSB.

To answer your question, YES you can use it. BUT the question also is, will the pins on your new FSB align properly with the notches on the barrel. If memory serves me right, some have different spacings (i may be wrong though). But should it be the same, then you will have no problem.

Posted: 9/29/2006 1:31:03 AM EDT

[#3]

Thanks for replies, gents, as I suspected the new FSB maybe will have to get fitted, hm, I will risk the cost of the new one in order to see if it's possible.

Posted: 9/29/2006 1:46:41 AM EDT

[#4]

voglio fare la stessa cosa per il mio Colt. Ho intenzione di comprare un FSB nuovo senza i fori per le spine e provare a fare i fori adatti alla mia canna.

avevo fatto la stessa domanda mesi fa e un certo Randall che lavora a ar15barrels.com mi ha spiegato passo passo come fare. Più tardi copio le istruzioni qui sul tuo post ok?

in bocca al lupo

edit to add:

You are going to need a new FSB (obviously) and a milling machine to acomplish this.
Then you need a 2/0 taper pin reamer and a 1/8" drill bit.
Tap the hole on the bottom of the new FSB for a setscrew.
You may have to remove the sling swivel rivet to access the hole.
Pop both taper pins loose, but only leave one of them in place to position the FSB on the barrel.
Clamp your barrel in the mill so the FSB is perfectly horizontal.
Use the taper pin reamer to center up over the empty hole of the FSB.
Without removing the barrel from the mill, remove the other taper pin and the FSB.
Slide the new FSB on to the barrel and position it perfectly horizontal like the old one was.
Use the setscrew you added above to hold the FSB in place.
Carefully drill through the FSB.
Beware that the drill bit acts funny when you are in an interrupted cut which will be 2/3 of the job.
Now ream the hole for a taper pin.
Remove the new FSB and swap back to the old one.
You will probably need to add a setscrew to the old one now too.
Install the old one with the same taper pin that you used while locating the first hole.
This is the reference to be sure it's in the right place.
Now tighten the setscrew to hold the FSB into place and remove the taper pin.
Align the taper pin reamer in the 2nd hole.
Swap the FSB again, drill it, ream it and you are done.

Yes, it's a serious pain-in-the-ass job.
That's why we build special fixtures for it...

[ARCHIVED THREAD] - (info req) Installing a new FSB

AR Sponsor

Warning

Confirm Action

[ARCHIVED THREAD] - (info req) Installing a new FSB

[ARCHIVED THREAD] - (info req) Installing a new FSB