AR-15 Screws Stuck - How to Remove

[ZigZagZeke]

It's done!!!!!!!!!!

I bought a pencil butane torch and tried heating the thread end of one screw for at least 2 minutes. I still couldn't budge it. I twisted the high quality allen wrench all the way around one complete turn without moving the screw.

I finally stripped out the head on that screw, so I felt OK about drilling it out. I used a #25 bit on slow speed and got nice long curls as I drilled into the head. When I hit the bottom of the head it popped right off with a rather loud snap. It must have been SUPER tight. The remaining shank was loose in the hole. I could turn it with my fingers until I couldn't reach the thread end anymore. Then I used a mechanical pencil eraser on the head end to back it the rest of the way out. I then did the same with the other three screws. There was no Loctite. Somebody had simply tightened the **** out of the screws.

I then removed the riser blocks and installed the scope and rings without the risers. Now I have about 1/2" of clearance between the 50mm scope end and the hand guard. When I throw the rifle up to my shoulder and put my cheek on the stock I now have a perfect sight picture. It's no wonder I got a good deal on it. It was very difficult to shoot it accurately the way it was. Now it fits and gives a very stable and repeatable sight picture.

Thanks for all the help and suggestions.

 

[The B]

weird... glad you got it figgered out.

 

[billdeserthills]

weird... glad you got it figgered out.

+1 To That!

 

[ZigZagZeke]

Just to follow up, I got a chance to sit down and examine the risers and the screws. The problem is the risers. There is a lot of clearance in the dovetails between the male cast-in rail on the receiver and the female part of the risers that fit on that rail. Since the risers are one piece, the mounting screws have to be tightened enough to distort the shape of the riser and squeeze it in horizontally so that it grips the cast-in rail. So the screw has to be tightened so that it squeezes the riser down probably .030-.040" after it is finger tight. Then the solid aluminum riser block acts as a really hefty spring applying pressure to the screw head. The snaps I heard as the drill cut the heads off the screws was this "spring" pressure being released. These risers seem to be standard equipment on all new Bushmasters and the screws are probably torqued down at the factory. This situation is probably present on all new Bushmasters, so if you are removing these risers from a factory fresh Bushmaster keep in mind that it isn't Loctite, the threads probably haven't been abused, and the screws are just mild steel and can be drilled easily.

These are 1/2" risers and I believe they are meant for use with something like a Red Dot sight. If you're mounting a 50mm scope you do not want to use "high" rings with these risers. Either remove the risers or use lower rings.

 

[oregonty]

I had the same risers on my rifle. I hate them. They are one of the worst designs if you ask me. They bend when installed and cause things to be out of alignment. I threw the darn things out. It made scope adjusting way out of whack.