taking flash sup off 12.5" w/ 11" rail?

[Wilco]

I have a 12.5 BCM upper with VTAC 11" rail on it, and want to swap out the flash suppressor with another.

I know the old "building block" vice grip trick using two pieces of wood around the barrel, but there isn't any barrel to grab on this one. Will I need to take the rail off (something I don't really want to do) to get the flash suppressor?

How tight usually does BCM put their fs's on?

Thanks for any suggestions!

[Marty916]

I would suggest that you pick up some armorers tools such as these so you don't damage your rifle:

http://www.bravocompanyusa.com/AR15-Action-Block-Upper-Lower-p/action%20block%20upper%20lower.htm

There is no telling how tight or loose a compensator may have been installed or if any thread locker or rockett may have been used.

[pcf]

If your handguard will clear the gas block and flash hider, I would take the handguards off. Then secure the barrel in a barrel clamp or pipe jaws.

I've bent an indexing pin trying to get a stuck flash hider off. Entirely my fault for being lazy and not using the right tools. I also read on here where someone wallowed out the notch for an indexing pin doing the the same thing. Prior to that I can't tell you how many times I had gotten away with sitting on top of an upper and remove or install a flash hider.

[Wilco]

there is about an inch of barrel, pre fs, sticking out from under the VTAC.

So, would you think I should definitely have something on the barrel and not just the receiver clamp/tool?

[Polymerhead]

there is about an inch of barrel, pre fs, sticking out from under the VTAC.

So, would you think I should definitely have something on the barrel and not just the receiver clamp/tool?

I'd loop a leather belt around the exposed inch of barrel and then get a smallish pipe wrench or vise grips and clamp them over the belt. Clamp that in a vise or just sit on it and use a crescent wrench or AR tool to try to remove the FH. Anything torqued under about 40 ft-lbs should come off that way without damage to the barrel. Anything more than that and you should remove the rail and vise up the barrel.

[Wilco]

ok, dumb question. how can i tell what 40 lbs of pressure will be? I hate that I am so non technical, but that is one reason I am here, to learn...

[Polymerhead]

If you're wrenched onto the barrel and sitting on the wrench, and using both hands to torque off the FH with a FH tool or crescent wrench, you're not going to hurt the gun so don't worry too much about what 40 ft-lbs feels like. That was just an estimate as to what forces you should be able to exert set up like that.

If it comes off, great. If not, you'll have to take off the forend.

Just use your common sense. Make sure you're not stressing anything too much. The only contact point should be the barrel with the belt/wrench in one hand and the flats of the FH with a FH tool or wrench in the other.

And make sure you're torquing the right way! :)

[Wilco]

left loosie, righty tighty!

thanks again