I want to whack off the front sight on one of my uppers and make it into a low profile gas block.  Would there be any harm to doing this while it is still on the barrel?  I don't have to remove it to do the dremel work, do I?  When it is all done I was just going to spray paint the sight and barrel.

I would advise that you take it off when you do it.

While i do not think that it will do any major harm If you choose to cut it while it was still on your barrel - I do believe that it would still be much easier for you (cut and buff and paint the FSB) if you removed the same first.

Just my .02 cents.

I did mine recently and took the FSB off the barrel.  The cut would be pretty easy, but you will want to grind it, round it off, and generally clean it up, which will be much easier off the barrel.  You might have it parkerized too

I have cut down two and left them on the barrel. I did remove the barrels from the uppers for the grinding part  though. Worked out fine.

I cut mine off while it was on the barrel. I took the handguards off so I wouldn't accidentally hit them, and used a dremel tool with a cut-off wheel, then rounded and smoothed things with a sanding drum. Lastly, I touched it up with some Brownell's Gun Kote, and baked it by leaning it near the woodstove.

I did the same to mine.  I created a varmint upper with my post ban barrel.  It is easier to work with the FSB once it has been removed.  Removing the FSB is not hard. Just make sure you are hitting the pins from the correct side.  If you are going to be able to see the gas block you will want to refinish the whole thing.

Be sure you really want to do this.  If you should decide you want to go back to the original configuration again, you will never find a FSB that fits your barrel as well again.

duuuhhhhhh, tacked to the top of this very FORUM is this: www.ar15.com/forums/topic.html?b=3&f=4&t=226782

Which contains FALARAK's excellent BIY instructions on:

Make your own cut-down low profile gas block, step by step:

Check it out.....

Mike

Quoted: duuuhhhhhh, tacked to the top of this very FORUM is this: www.ar15.com/forums/topic.html?b=3&f=4&t=226782 Which contains FALARAK's excellent BIY instructions on: Make your own cut-down low profile gas block, step by step: Check it out..... Mike

I have read that post several times.  I was just wondering if the hassle of removing the FSB could be avoided.  Thanks for the input.

I just chopped my gas block. I left it on the barrel and used an angle grinder, not a girly Dremel

I used a longer hg that covered the block so it didn't matter much what it looks like...

Actually I had to take it off the barrel but I felt it was easier to hold the whole upper while chopping the block instead of putting just the small FSB in a vise, cutting a bit, taking it out of the vise, turning it, putting it back, cutting, taking it off, turning etc ad nauseam

I put two free float hg's on two uppers and removing the FSBs was an epic quest on both, I would do a lot to avoid ever having to struggle with them again