Briman

Yes its removable, but it looks like a PITA.

Its screwed on, and also pinned sort of through the edge of the launcher.

If you remove it, for legal reasons, you need to replace it with a muzzle brake or flashhider that is screwed on and welded into place.

The 59/66 falls under some really screwy nonsense law in which its only to imported as a C&R and if you try to add evil features like a folding stock, a hi-cap detachable magazine, or a threaded muzzle, you have to convert it into an 'American made' rifle by swapping in enough parts that are stamped 'Made in USA' so that less than 10 of the rifles parts foreign made. Make sense? Didn't think so. Don't worry, it doesn't seem like even the BATFE understands the law either.

I'd just buy one and leave it as is, they shoot really nice and are a blast to shoot. I just picked one up a couple of weeks ago and had no problems whatsoever popping off soda cans at 50 yards shooting from my feet. I didn't bother shooting it off a bench as the there is so much junk hanging off the barrel, and I would have to extend the bayonet in order to not put pressure on the barrel when shooting it from a rest.

I paid $150 +tax for mine, it came with a book that had stampings and signatures showing that it was made in 1983, was testfired, and was inspected every 5 years or so. Its a neat gun, more fun than $150 can normally buy you.