Question regarding the Bushmaster .450 upper

[firehawk1]

I've got a .450 16" upper coming and have a few questions regarding the handguard.

I assume it is possible to remove/replace the tubular handguard that comes on this upper with a Magpul MOE handguard. I just don't really care for the tube style handguard, and all my other uppers have the MOE on them and I'd like to keep all the uppers the same.

First, is the gas block on the .450 pinned, or set screwed on? I assume I will need a delta ring, spring washer, and front end cap. Any other parts I would need?

Second, removing the tube handguard seeing that I don't know how it's attached, is that something I can do or should it be done by a gunsmith/armorer? If it isn't something I can do, can the AR guru at Bradis (sorry don't recall your username) remove and replace the handguard?

 

[Adrian8]

I have a 20" upper.. The handguard should just unscrew and come off. The gas block has two set screws holding it on

 

[firehawk1]

I have a 20" upper.. The handguard should just unscrew and come off. The gas block has two set screws holding it on

It is my understanding that the 20" upper has two gas blocks. One is a "dummy". Are you saying both of the gas blocks use set screws?

As far as unscrewing the handguard, does that imply that there is a different barrel nut on an upper that uses a free floating handguard than the nut on a non floating handguard?

Sorry for what might seem stupid questions but I'd like to make sure I understand everything so I get all the parts needed to swap the upper over to the MOE.

 

[Adrian8]

mine has only one gas block and it appears that the handguard would slide over it without taking off the gas block.