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View Full Version : AR-15 front sight base with roll pins? Q: Flash suppressor removal?


shooterx10
02-21-2007, 10:53 PM
Has anyone seen an AR-15 front sight base with roll pins instead of taper pins? Who makes this? Is it easy to take off once the pins are out?

Also, I'm trying to take off the dumb A2 flash suppressor, but it won't budge. Any suggestions?

Technical Ted
02-21-2007, 11:12 PM
Sorry. Can't be good if they used roll pins to hold the FSB in place. Definitely not a US military spec barrel.

Any stamping near the muzzle that indicates twist and/or chambering?

Is this a used barrel? Are you using barrel vise blocks? Carbon and residue can build up in the threads and make removal difficult without soaking in solvent.

kap
02-21-2007, 11:19 PM
According to the AR15 How To guide RRA and LMT may have straight pins.

Now we need to remove the FSB (front sight base) from the barrel. The pins in the FSB are typically tapered. This means they can only be removed one way. (I am told that RRA and LMT use straight pins, not tapered, so those should be even easier) Look on both sides of the FSB and determine which side of the pins is the SMALLER end. It should be the left side, and we will be knocking the pins out from left to right. NOTE - Stag Arms has been shipping uppers with FSB taper pins on the opposite side of most uppers - so be sure to examine your FSB!

http://ar15.com/forums/topic.html?b=3&f=4&t=226782

shooterx10
02-22-2007, 9:25 AM
Is this a used barrel? Are you using barrel vise blocks? Carbon and residue can build up in the threads and make removal difficult without soaking in solvent.

The barrel is used, but there are no markings on it. I've seen Vulcan and Hesse builds and the quality of this is better than there's. Do you recommend using something like Liquid Wrench on the A2 flash suppressor?

http://www.gunk.com/product_images/SM_L112.JPG

I might send the upper to ar15barrels.com and have them deal with it. They post on arfcom and I've read their rep is quite good and they are in CA. I have a workbench (for reloading), but it's not sturdy enough to do the work that is required here.

shark92651
02-22-2007, 11:32 AM
Is there a posibility that the flash hider is pinned in place? If not then perhaps it has locktite on it. Maybe you should take a torch to the end and heat it up to 500 degrees. I also assume you are using a good vice and some barrel blocks to hold it in place while you apply the muscle to it. It was not necessary on my upper - in fact I was able to get it off by just holding the rifle between my legs and using an adjustable wrench. I have an action block and vice now so I will not be using that technique anymore :)

grywlfbg
02-22-2007, 11:33 AM
Brute force, ignorance, and a barrel vise is all you need to remove the muzzle device (unless they welded it on). I made my own barrel vise out of a couple 2x2's - search on the forum here and you'll find the post.

I'm about to swap the FSB to get rid of my A2 front sight (going optics-only on this upper). And right now I'm looking at my RRA 16.5" upper purchased last month and the pins are definitely tapered w/ the small end on the left. YMMV.

Chris

Technical Ted
02-22-2007, 12:04 PM
I'm looking at my RRA 16.5" upper purchased last month and the pins are definitely tapered w/ the small end on the left. YMMV.
Taper pins are the "gold" standard. Even on the venerable SPR barrels, the gas blocks have been secured by taper pins.

Bushmaster, Colt and FN barrels are tapered right to left (small end on right).