Upper reciever swap with pinned muzzle deceive on barrel assembly?

AR/M4 AR Technical Discussion
1

Is it possible to swap uppers without removing the FSB and muzzle device?
A family member has a Bushmaster A2 upper with a carbine FSB on 14.5" barrel with pinned muzzle device.
Am I correct in thinking an upper receiver can be swaped by removing the gas tube and simply wrenching on the barrel nut?
Of coarse the POS upper/ barrel extension does not have M4 feedramps, I would need to find a flat top upper w/o M4 feedramps.

Thanks.

2

Correct.

3

Are swapping uppers or changing barrels? If you want to change a barrel, you are correct. If it is the whole upper, just push your pins out and separate the upper from the lower.

4

Ask and ye shall receiveth- http://www.bravocompanyusa.com/Upper-Receiver-Assembly-M4-Flat-Top-demo-p/flat%20top%20-upper%20-m4%20demo.htm