AR15 Front Sight Pin Removal Problem

Intarsiac · Jan 28, 2010

I'm trying to remove the A2 front sight tower on my AR15. I got one pin out, the second refuses to budge. The pins are tapered and must have been factory installed with a press. Whacking after soaking overnight in WD 40 didn't work. Whacking after heating with a hair dryer didn't work.
Would applying a torch flame damage the finish on the sight tower or barrel?
Would freezing for a few hours help?

Looking for ideas before resorting to drilling it out and replacing the pin.

Why? I'm seeing if I can remove the sight tower and replace it in anticipation of a future free float quad rail installation, plus I had to try out my new torque wrench in replacing the barrel (worked fine). That and I can never leave well enough alone.

boatbod · Jan 28, 2010

Presumably you already figured out that you have to drive the pin out from the correct side. After that its pretty much a matter of heating up the sight base with a heat gun or torch and then beating on the pin with a correctly sized punch. Make sure there is appropriate support under the gas block so your punch doesn't slip off at an angle.

A hydraulic press would make the job easier.

midcountyg · Jan 28, 2010

I have seen them extremely tight before, and had to use a mill to cut part of the way through the pin. When I have done that it ruins the sight tower, but I was replacing it anyway. It is important that the pins are driven the right direction though, and a front sight block from Brownells is very helpful.

alucard0822 · Jan 28, 2010

You need to secure the sight base/barrel somehow, preferably in a vise, heat can help with really stubborn pins, a hair dryer won't cut it, you need a torch, don't want to get it glowing, but about 500 degrees directed to the bayonet lug or sling loop base won't damage anything, line up a punch, and smack it hard with a good sized hammer. You do not want to clamp down on the barrel, clamping on the base is fine, or supporting it from underneath as you can damage the barrel if it is not supported while hammering on it. If you keep hitting it too light, the end will peen over, and you will need to slot into the base all the way to the pin to get it off. Drilling out the pin is not a good idea, being it is easy to damage the barrel, and being they are tapered, there will still be some of the pin left in the hole. With a little heat, and the base secured, there are few pins that won't come out. It is also a good time to change the gas block if that is in the plans. If you are using a clamp on block, I usually gently hammer the pins into their place in the barrel with some red lock-tite, then file them down to match the contour of the barrel, and if that portion is bare metal, I either duracoat the entire barrel, or use some matte black/parkerizing touch up to protect the metal, when it's done you can't tell where the barrel was drilled for pins.

Intarsiac · Jan 29, 2010

Thanks for the tips! However, no luck with the torch, correct sized punch, correct direction, and everything securely clamped down. I think the end of the pin is probably now peened. <Fail> I'll wait until I actually get a quad rail and then attack the sight tower removal again. For now everything is back together.

AR15 Front Sight Pin Removal Problem

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