Forearm swap?

Talk about the AR15 style rifles chambered in 450 Bushmaster.

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Forearm swap?

Postby Crawlin » Mon Mar 08, 2010 3:45 pm

Newbie here! Just ordered up a .450 upper since the price is hard to beat. Looking to change the handguard that's on it and gas block. Gas block from the search looks to be the same as a regular 5.56 setup and size.

My question comes with the forearm... is it pretty much the same as the plastic M4guards in regards to removal? Or is it a bit more involved then that as if you were installing a YHM or M.I. rail? I was looking at some of the Troy battle rails that drop into a "stock" ar's plastic mounts, but don't want to purchase that if it's not going to work. Thank you for your time!

Chris
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Re: Forearm swap?

Postby MudBug » Mon Mar 08, 2010 4:31 pm

If it's the free float fore arm (I think all they make) then it's kinda like the old YHM FFHGs. It has a round barrel nut with threads on the outside, a jam nut and the hand guard. The jam nut is on first then the handguard is screwed in and the jam nut is then tightened up against the handguard.

They are not hard to remove.
Eric

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Re: Forearm swap?

Postby Crawlin » Mon Mar 08, 2010 5:02 pm

Thank you very much! Just excited to get this thing, haha.
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Re: Forearm swap?

Postby MudBug » Mon Mar 08, 2010 6:58 pm

oops, I forgot to say that yes, the gas block is standard AR size.
Eric

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Re: Forearm swap?

Postby CorpDavid » Thu Apr 01, 2010 12:48 pm

The gas block is .750 in size, and has 3 set screws to hold it on.
Handguard is a metal tube and uses a barrel nut that the tube screws onto. Thats as far as I gotten on replacing the forearms.
Trying to decide on the free float rails that I want to put on the Thumper.
I have a Daniel Defense Omega 7, but it uses a standard Barrel nut not the barrel nut that comes with the tube.
So I think I have to remove the barrel nut with a barrel tool that has the pegs type that fit the holes in the barrel nut.
Then replace with standard barrel nut with the grooves around the outer perimeter of the barrel nut. :geek:
Or, purchase another Free Float rail that has it own barrel nut. 8-)
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Re: Forearm swap?

Postby 2zero6 » Thu Apr 01, 2010 12:58 pm

If it is the 20" there are only 2 set screws on the low profile non railed FSB.
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