View Full Version : change front sight on ar-15

July 15, 2009, 08:10 PM
I have a S&W M&P15 and I was thinking about getting an EOTech sight for it. I was wondering if it is possible take the front sight off and put a flip up one on. I want to still have the option to go back to the iron sights. I was thinking something like:http://www.mountsplus.com/miva/merchant.mvc?page=MSP/PROD/AR-15-SIGHTS/41B

Is this doable? is there a guide online? I cannot find information on it.

Any .45
July 15, 2009, 08:55 PM
I'm guessing you have an A2 front sight/ gas block. If so here is what you do.

First off, follow the safety rules and unload your gun, take all ammo out of the room.

You will be happy to know however that you can replace it your self with quit a bit of ease.

All you need to do is knock out the 3 pins on the front sight post with a punch and hammer. A lot of guys say you need a block to work on but I never used one a hockey puck works just as well.

First you have to remove the upper from the lower, flash hider, and handguards from upper.

Put the puck or a pice of wood under the front sight post to prepare to take out the pins.

Now you have to knock out the pin that holds the gas tube in the front sight from left to right and then take out the two pins that hold the block to the barrel from left to right as well. Be carfull try not to mar the pins cause you will want to reuse them they should come out easy.

After you have all the pins out you should be able to wiggle the sight post forward off the barrel. If it sticks give it a small tap with your hammer if you have a dead blow or lead hammer thats even better.

Now there is a watch out. The watch out here is that the flash hider may be pinned and would have to be cut off. This is the Assault Weapons Ban stuff - no removable flash hiders or brakes. Of course the Federal AWB is not now in effect, but there are several state versions that are as or more restrictive than the feds, so many manufactures just pin the hider so they don't have to keep track as whether an upper is legal in a particular state.

Hope this helps you.

July 15, 2009, 09:47 PM
Yankee Hill Machine

July 15, 2009, 10:50 PM
Any .45, thanks for your quick response, doesn't seem too difficult. But I looked on the YHM site as DnPRK said and they have free instillation. DnPRK, have you had them install something before? would I have to ship my rifle to them? I emailed them asking this question, but obviously they aren't there to receive the email at this moment.

July 16, 2009, 08:32 AM
YHM does nice work and they have a (relatively) good turn around time. I think you can send them just your upper for th installation of the front gas block which cuts down on the shipping cost as you are not sending a firearm. if you strip off the forend you'll save a bit on the package weight as well.

Before sending it off, have a look at AR15.com. There are a lot of how-tos posted there that can walk you through the gas block replacement. This is not a difficult task.


July 25, 2009, 09:49 AM

watch the video and decide if you want to tackle it.