I’ve done this a couple times. Cut off with dremel, smooth it down with a table top belt sander, hit with some cold blue and you’re done.
That's how my blackout and Pdog 5.56 are done...but they both have 15" handguards on 'em so they go well beyond the gas block. I've had zero issues with it. It works for a home build...I'd be kinda upset if I paid for a "gunsmith built" upper and thats what they did.