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1/25/2018 7:38:29 AM
Posted: 6/26/2003 4:34:21 AM EST
Alright guys, just to be clear, I checked the Maint. area and there was one post with 1 response on this issue, and I wanted to get a little more visability and another view on this. I recently purchased a 3rail Gas block MAS. It replaces the front sight and has a removable flip up front sight and side rails.
1.) has anyone installed one of these?
2.) I am having a hard time removing the front sight pins. Do they punch out to the right (as looking toward front) and what is the best method (you have used persoanlly or seen, NOT in theory) to remove them without a vise and workbench.

I appreciate all of your help, and will understand if this gets relocated but only one person was nce enough to reply to the post in Maint and I guess this seems to be the main viewing board. Thanks for your help.
Link Posted: 6/26/2003 4:57:41 AM EST
I've tried to remove the front sight before and failed. All I did was scratch up the finish. They really put those pins in tight. Some people here have had similar trouble, others seem to get them right out. I think they go out from left to right, when holding the weapon as you would when firing. I wouldn't attempt this without the right tools, and a vise is one of them. Good luck. Steve.
Link Posted: 6/26/2003 5:19:38 AM EST
OK. I was not sure, because I had a Free-Float tube installed so it was removed before and I was right there when he did it, but I forget if he used a vise (probably did) I have such a h@rd0n to put that rail block on because I bought the light mount and front sight. Guess its off to the gunsmith
Link Posted: 6/26/2003 5:26:14 AM EST
Give it a try. The wost thing that will happen is that you scratch the finish or the fornt sight. That really doesn't matter if you are going to put on a new gas block. I just remember saying to myself I wish I had a vise when I tried to take mine off.
Link Posted: 6/26/2003 5:29:49 AM EST
When I first called Bushmaster, the guy I talked to told me it really should be an inhouse job. I thought what the hell for, it is just a front sight swap. So I ordered it anyway. Get a set of punches, and drive out the pins in your front sight base. They move from left to right. Simple terms, push them from the side without the ejection port, they come out on the side with the port. The MAS block does not use the pins. Drive out the roll pin that holds the gas tube to the font sight. Dont lose it, you need it. That should leave you with the gas tube in your hand. Push it into the MAS block, and drive the roll pin back in. There are special punches for roll pins, that have a dimple that lines up the pin and punch. But, a punch that is larger than the pin will work fine. Then just slide the MAS block back over the barrel. Line up the tube, push it through the handgaurd ring and into the receiver. Push the MAS block till it is tight against the ring. Then, there are set screws in the bottom of the tighten them till they just touch the barrel. For making certain that the block is straight, it is nice to have a receiver block and vice, but not neccesary. If you don't have one. just remove the upper, and set it upside down on a flat surface. a small level works best here. Place the level on the bottom of the MAS block, and see that it is level. Make sure your surface is also level. This is easiest with Flat top guns, but will work with an A2 upper also. jsy make sure the gun is level first, then make sure the block is level. If it is, tighten the set screws in the bottom of the block. Use some LOC-Tite also at this point. Blue is good, as it sets very well, and isn't as hard to undo as Red is. Put the drift pins from your A2 sight back in the old sight, so you dont lose them. Then toss the sight in a parts bin. Now, let the LOCtite set and go sight it in. Mine was dead on, using the Bushmaster rear flip up sight, with the front flip up. They stay down most of the time, but work well as a back up the the EOTech. Any more questions, or more detail, let me know. -Kirt
Link Posted: 6/26/2003 5:45:08 AM EST
Thanks Kirt. It is nice to hear that someone else did the same. I appreciate you taking the time to go that into detail. I will stop and pick a good set of punches, (I need some anyway) and I will let you knwo how it goes. Thanks again. That is perfect info
Link Posted: 6/26/2003 6:34:18 AM EST
No problem, glad to help out.
Link Posted: 6/26/2003 10:15:38 AM EST
One pin came out easy as pie in 30 seconds. The other took cutting the front sight tower for an hour with a Dremel tool and a rain of sparks flying everywhere. It was so tight it would not move from a hit with a sledgehammer.
Link Posted: 6/26/2003 10:45:48 AM EST
FWIW: I have seen the pins drifted in from either side, I guess it is up to whoever drilled and reamed the holes as to how the barrel was put on the machine.
Link Posted: 6/26/2003 10:57:40 AM EST
Here's what I did for a stubborn front sight tower. I'm not sure if one thing worked or if it was a combination of all of them. Soaked in penetrating oil. Pound w/ hammer and punch. Heated with blowtorch.Pound w/ hammer and punch. Placed in freezer overnight. Use the largest and heaviest punch you can find that will still fit in the holes. Hammer away with a heavy hammer. Mine were in there TIGHT and I finally got them out. Touch up scratches with perma blue paste and they disappear. Have fun!
Link Posted: 7/1/2003 4:22:02 PM EST
I measured the pins with my caliper and found about.004 taper with the pin coming out the same direction the shells eject ! I beat on it with a machinists punch and a BMFH. No luck. So I heated the sight with an Acetylene plumbers torch. Drove one pin out. Heated it again with the torch and drove the other pin out. Had to beat the sh8 outta them tho until they moved, and then they were really loose. I then put the sight in the vise and used my high speed grinder to take the top off. Then milled a flat on what was left of the gas block and put it back on, after I installed the free floating fore end. Roger
Link Posted: 7/2/2003 4:42:00 AM EST
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