Are FSB "married" to barrels?

[TMS951]

I have a 14.5" DD CHF barrel. I shaved the FSB to fit under a rail.

Now I have decided I want to go back to using that barrel with a FSB and I want to use the rail with a DD CHF 16" barrel.

Could I order a DD 16" barrel with a FSB, take the FSB put it on the 14.5" barrel and put the shaved FSB on the 16" barrel? Same barrel profile for each, same manufacturer.

Basically will the pins line up?

[Joeywhat]

Possibly, but not likely the holes will line up.

Considering it's from the same manufacturer, they very well may use a jig to drill the holes, so they may line up fine.

[Nutro]

Possibly, but not likely the holes will line up.

Considering it's from the same manufacturer, they very well may use a jig to drill the holes, so they may line up fine.

Yeah I thought my brother was full of shit when he told me my holes wouldn't line up. He was right.

[Evil Bert]

I would call up DD and talk to them. Ask them if they use a Jig type setup for all their FSB's. If they do (all manufactures likely do, just different jigs) you have a good chance of it matching. Before you do anything call DD and ask. They may be able to help you out.

Also for those if you looking to or considering shaving the FSB down, you may want to think otherwise. It works yes, but brings problems of it's own such as this one above. If you change you mind, well...

[kwelz]

No you can not. Each one is drilled individually and unless you somehow get very lucky they are not going to match up.

[ccosby]

No you can not. Each one is drilled individually and unless you somehow get very lucky they are not going to match up.

Yea generally speaking it isn't going to work. You can get a new fsb and drill it to work with the barrel but it isn't easy to do.

[lamarbrog]

I've always wondered why this is the case- is it really that hard to come up with some set dimensions for this and standardize?

Even if the military doesn't do it, you'd think the manufacturers could get together and come up with a spec for this- Kind of like how SAAMI works, except barrels/FSBs instead of ammo.

Sure would make life easier...

[jet66]

I tried to swap the bayo-lugged FSB from my 6920 to my older Colt A2 whose FSB is w/o bayo lug: Close, but no cigar. With it in place, the front pin lined up about dead on, the second was off by about 1/32" or so.

[Tweak]

Plenty of shops remount new FSBs on drilled seats. Takes a little skill and, at least, a very solid drill press to do it though. For the cost and hassle you might as well buy new and sell the old.

[Iraqgunz]

I doubt it. We still can't get manufacturers to stop making silly commercial lower receiver extensions or do simple thigns like stake castle nuts and bolt carrier key screws.

I've always wondered why this is the case- is it really that hard to come up with some set dimensions for this and standardize?

Even if the military doesn't do it, you'd think the manufacturers could get together and come up with a spec for this- Kind of like how SAAMI works, except barrels/FSBs instead of ammo.

Sure would make life easier...