Recentlly got a BCM recce upper with DD Lite rail and am wanting to put a PWS FSC556 compensator on it.
I’ve never changed out a flash hider before…am I going to need to take the rails off of the upper to get the flash hider off without wrecking anything?
Nope. Just unscrew it.
Unless you can hold the barrel tighter than I can, you may need a set of aluminum barrel blocks between the FSB and the FH. Just noticied that mine are about two blond ones too long to fit on a Middy- and my FSB is in front of my 9" rails.
So I am going to need to vise the barrel (as opposed to the upper receiver or rails) down to unscrew it without tweaking anything?
This is the upper so I really don’t have a lot of barrel real estate to vise on to. If I do have to vise onto the barrel to unscrew the thing (from what I’ve read flash hiders are usually on there really tight) I guess I will have to take the rails off. Hoping I could have avoided that step.
Hold upper with left hand, use 3/4" open ended wrench in the other hand. Looking down the barrel from the receiver to the flash hider turn the flash hider clockwise.
Flash hiders that are secured with a crush washer are usually not that hard to get off. You’d really want to use a barrel block if you were trying to break Rockset or something like that. Just a crush washer will not be hard enough to worry about breaking anything like the pin that aligns the barrel into the upper. Besides that its torqued down by the barrel nut. You can put some thin tape over the flats on the flash hider if you are worried about any marring.
Install the brake according to the directions, and you’re done.
+1
I like to hold the upper rec. in my bare feet and put my left hand on the FSB or rails, and turn with the right. I put the tape on an adjustable wrench and close until it’s a perfect fit.
The best way is to clamp the barrel in barrel blocks in the vise to remove the flash hider. This way you’re not trying to spin the barrel within the upper receiver.
Using some pieces of 2x4’s (I can clamp them together, drill a barrel sized hole and then unclamp them and vice the barrel inbetween them) should work for this without marring up the barrel right?
Yes this will work great. Just make sure that the barrel sized hole is actually slightly smaller than the barrel. That way there will be more pressure placed on the barrel.
Use Oak if you can. Always clamp the barrel tighter than you think you need to - if the barrel spins in the blocks it will mar the finish the most.
what’s the reason for oak? harder then the other woods?
Correct on the hard wood, but it might not matter for a barrel block. Not that I’ve used a wood block for a FH removal, but from people who have used similar for building FALs, Oak is preferred. Scrap Oak can be found in heavy duty wood pallets, btw.
It depends on how much force is required to remove the old FH and how much is needed to Index the new one.
I wanted to do the same stuff as the OP on my Noveske built upper. I ended up buying a set of aluminum barrel blocks from Midway for around $25, and cut them down about an inch to fit the limited exposed barrel. Glad I spent the money, as the FH was super tight. I actually lined the blocks with a layer of sheet polyurethane to improve grip and avoid marring (OCD?)
Good advice from GOTM4; use proper equipment to avoid expensive damage. Heck, Rob offered to do the deed if I was willing to drive up to his shop. Only on M4C have I seen people willing to help out a fellow shooter to this extent.
You can borrow my blocks if you live around Southeast VA.
Mark
Good advise, I’ve marred a few and it does tend to piss one off. Was your original FH a Vortex?
The one I’m thinking of changing is also on a Noveske, although I bought the N4 Reece Basic upper and later added a 9" Omega rail. My barrel blocks will only need a hair of modification and would not even need that except for the barrel sleeve on the Vortex.
I speced it with an AAC Blackout. Changed it to FSC556, as the OP wants to do. Noveske indexed the AAC, and boy was it tight. Used wooden blocks first without success. Actually broke the vise, trying to keep barrel from rotating. Got the proper blocks, lined them, and a new vise. Would not want to mess up a BMC upper either.
Mark
I’m going to email BCM and ask how many ft/lbs they tighten the FH’s on their uppers.
that should help me determine if I need to just nut up and buy some aluminum blocks.
Where did you get the polyurethane sheets?
Blackouts are supposed to be Rocksett’d on so if they did that it would explain why it was so hard to get off.
A normal A2 with crush washer would be much easier.
I have done two (plus removed stock A2)FH replacements on same upper … every time I used thick double thick cardboard vise padding and the on/off’s went very easily with no slippage or marring… my last FH was indeed a PWS FSC 556 and they are not to be torqued on very hard … If memory serves …you are to index it by having the FH start touching the provided split washer at the 10o’clock pos and then tighten to 12 …
H
Are you supposed to use blue loctite when putting the fsc556 on?
No. If I get them to time with indexing washers and little torque I’ll sometimes use Rocksett.