Taper pin reamers

[CrowCommand]

Looking at fitting an f marked a2 FSGB on a barrel previously fitted with a different one. The cuts in the barrel are a c-hair off, or the taper pins are a bit large....I’ve been told to run a taper reamer thru the pin holes. Anyone know how to go about this?

[titsonritz]

Looking at fitting an f marked a2 FSGB on a barrel previously fitted with a different one. The cuts in the barrel are a c-hair off, or the taper pins are a bit large....I’ve been told to run a taper reamer thru the pin holes. Anyone know how to go about this?

This isn't a garage fix, you need a jig to hold the FSB in correct relation to the barrel. I'd suggest taking or sending it someone with the proper equipment and know-how.

[lysander]

Get a 2/0 taper reamer and touch-up the holes.

[okie]

You can definitely ream the holes to mate up together, but that doesn't mean that the sight will be square when you're done. One trick people have claimed success with is to use vise grips to hold the front sight in position. The bands are just flexible enough that you can vise grip them tight around the barrel. So hypothetically you could align the sight, vise grip it in place, then blend your holes. As for aligning it, that involves a precision level and a plumb line.

You will also need overlength taper pins from McMaster. 2-0 just describes the taper rate, not the diameter of the start and end. You'll have to get long ones and trim them to fit.

Also make sure you go SLOW. If the holes are already as close as you say, a few hand turns will do it.

[CrowCommand]

Thanks, I have access to a machine shop, and the 2/0 is what my "supervisor" aka buddy/machinist recommended. Not trying to hack this, I have a FS bench block en route.....plus a spare FSB if I eff it up.

Looking at spiral flute 2/0 reamer 0.1462-0.1137" at Mcmaster now....I like the the vice grip idea, I may try that after I mark the TDC of the barrel. Appreciate the advice.

Happy new year folks.

[CrowCommand]

Reamer came in this afternoon, and I had some time to go work on the upper. It worked great. We put the FSB in place before installing the rail, cleaned up the c hair impeding the pins in the barrel grooves. took the fsb off, and reinstalled w/ the railand sen the pins home. Satisfying work. RIS II installed with FSP on a Colt 14.5 SOCOM. Can't wait to shoot this rig.

Thanks again for the advice.