My bad - I used the word tapped, when I actually meant reamed. Learned something new today. In any case, “good luck” isn’t exactly the kind of assistance I was hoping for.You see any threaded parts in the stuff you have? No threads means no tapping.
The biggest problem is securing the front sight straight in relation to the action.
The second biggest problem will be drilling into the rounded edge of the FSB in the correct spot.
IIRC those holes are tapered and so will require special reamers to create that.
Good luck finding someone to do that work and do it properly.
Drill and Tap AR Barrel for FSB?
- Thread starter MtlGarrett
- Start date
Just some comments on this job...
The FSB must be accurately located on the barrel journal. The tower must be vertical, relative to the receiver. If it isn't, it will be very obvious.
Drilling involves not only the holes through the FSB, but "half holes" in both the FSB and the barrel.
The FSB must be solidly held in position while the holes are made. Once the pilot holes are through, the taper reamer is used.
The drill has to cut in the FSB and barrel without running out even though the FSB and barrel are not made of the same material.
A really good setup is required. When the drill bit reaches the barrel there may be a tendency for the bit to attempt to run out, or for the FSB to turn on its journal. It might even be preferable to use a milling machine and small diameter end mill to make the holes. Curved surfaces and "half holes" aren't a problem for an end mill. The job needs to be done in a shop with the proper equipment and experience.
If the shop isn't local, round trip postage will probably run eighty bucks or so. Then there is the cost of the work.
A good clamp-on FSB is much easier to install, and is cost effective.
If you want a pinned FSB installation, go for it. But it isn't the only effective option.
The FSB must be accurately located on the barrel journal. The tower must be vertical, relative to the receiver. If it isn't, it will be very obvious.
Drilling involves not only the holes through the FSB, but "half holes" in both the FSB and the barrel.
The FSB must be solidly held in position while the holes are made. Once the pilot holes are through, the taper reamer is used.
The drill has to cut in the FSB and barrel without running out even though the FSB and barrel are not made of the same material.
A really good setup is required. When the drill bit reaches the barrel there may be a tendency for the bit to attempt to run out, or for the FSB to turn on its journal. It might even be preferable to use a milling machine and small diameter end mill to make the holes. Curved surfaces and "half holes" aren't a problem for an end mill. The job needs to be done in a shop with the proper equipment and experience.
If the shop isn't local, round trip postage will probably run eighty bucks or so. Then there is the cost of the work.
A good clamp-on FSB is much easier to install, and is cost effective.
If you want a pinned FSB installation, go for it. But it isn't the only effective option.
I appreciate the detailed comment. Unfortunately I’m not equipped with a drill press at the moment, nor would I want to take on this job even if I did have one - I’d rather not experiment with a brand-new barrel and run the risk of ruining it due to lack of experience. Ideally I’m still hoping to find an experienced gun smith to ship this out to.
Without the proper jig to hold it all in place, I can see why Tac Ord. would turn the work down.
I'd be leery of another shop saying they can do it for you and would question them on whether they have the jig or a suitable solution to replicate it.
Another option (that you haven't solicited for...) is you find an existing AR barrel and pinned FSB all ready to go (probably cheap in the EE).
I'd be leery of another shop saying they can do it for you and would question them on whether they have the jig or a suitable solution to replicate it.
Another option (that you haven't solicited for...) is you find an existing AR barrel and pinned FSB all ready to go (probably cheap in the EE).
Non-phixion
CGN frequent flyer
Contact calgary shooting center I had them do one a few years back on a retro build.
My bet is they were originally done with a jig to hold the barrel and FSB in the correct orientation and then a drill guide to keep the drill straight. That would be the fastest way to produce those holes.
It'd need to be a pretty small and longish end mill to go all the way across the FSB.
