(Solved) Upper receiver with broken off forward assist roll pin

[bigshoe83]

Sounds like it's likely deformed enough to prevent removal without an assist. Drill it. Variable-speed rotary tool with high speed micro-bits is what I'd use.

Thanks, I will try that


Sent from my iPhone using Tapatalk

[rpoL98]

is the pin bent or askew? i.e. top part of roll pin is in the upper part of the roll pin hole, bottom part of roll pin not aligned with bottom part of roll pin hole, and is now pounded into adjacent solid part of FA bore? can you ascertain (fancy fiddy cent word) this by looking into the FA bore with a bright light? if so, maybe only alternative at this point is to use a flat blade screwdriver and bend the pin into the major part of the FA bore and push it down from the top. or bend the pin back into alignment so that a pin punch can be inserted in from the bottom to push it back out the top.

it might deform part of the top half of the roll pin hole, but if you really want to salvage this upper, there should be enough roll pin retention pressure from just the bottom part of the roll pin hole.

is this some kind of Gucci upper? otherwise, stripped uppers are cheap enough, you're expending more manhour "costs" than what a replacement stripped upper costs.

it's the principle of the the thing though, right?

[lysander]

If it broke, it probably bent before it broke.

Start with a drill slightly bigger that the inside diameter of the roll pin and work up.

[cutter_spc]

I wouldn't try drilling the pin out through the pin hole, this idea will probably go south in a hurry. Get a dremel with a carbide bur bit and cut the pin off through the FA hole. then use a punch through either side to drive the pin out. Or you could strip the upper and soak the whole thing in Alum, not sure what this would do to the finish, might test it first, but it will eat the steel pin away and won't hurt the aluminum.

[bigshoe83]

It’s no Gucci upper but I don’t want to just trash it yet. Thanks for the advice.

is the pin bent or askew? i.e. top part of roll pin is in the upper part of the roll pin hole, bottom part of roll pin not aligned with bottom part of roll pin hole, and is now pounded into adjacent solid part of FA bore? can you ascertain (fancy fiddy cent word) this by looking into the FA bore with a bright light? if so, maybe only alternative at this point is to use a flat blade screwdriver and bend the pin into the major part of the FA bore and push it down from the top. or bend the pin back into alignment so that a pin punch can be inserted in from the bottom to push it back out the top.

it might deform part of the top half of the roll pin hole, but if you really want to salvage this upper, there should be enough roll pin retention pressure from just the bottom part of the roll pin hole.

is this some kind of Gucci upper? otherwise, stripped uppers are cheap enough, you're expending more manhour "costs" than what a replacement stripped upper costs.

it's the principle of the the thing though, right?

[bigshoe83]

I will try that, great idea. This I why I asked the question, I knew I would hear ideas I hadn’t thought of.

I wouldn't try drilling the pin out through the pin hole, this idea will probably go south in a hurry. Get a dremel with a carbide bur bit and cut the pin off through the FA hole. then use a punch through either side to drive the pin out. Or you could strip the upper and soak the whole thing in Alum, not sure what this would do to the finish, might test it first, but it will eat the steel pin away and won't hurt the aluminum.

[CMV]

If it's "too short" that means it's only engaged in one hole? Can't grab with some needle nose & just work it out that way?

[bigshoe83]

In the first pic you can see how short the pin is. The second shows the top side and obviously a previous owner marred it up doing something. The third pic shows the bottom hole.


Sent from my iPhone using Tapatalk

[CMV]

Pic #1 is the end of the roll pin only about halfway thru the channel for the FA? So the bottom is unobstructed? If that's the case I'm gonna go with "hit it harder" I'd use a flat punch & not a roll pin punch to hit harder also. Maybe even a 2lb hammer......

[tehpwnag3]

Thanks for the pics. You really ought to use a dedicated roll pin punch that has the nipple on the tip. This will keep the punch from slipping off. Still doable with a flat punch though.

Get some penetrating oil in there. Buy a cheap white plastic cutting board. Cut two strips wide and long enough to use as vise jaw pads on the rail and underside of the receiver surfaces. Clamp it good and snug in vice, but don't gorilla crush it. Now, tap the pin out from the bottom side hole. With this setup it'll be easy.

If you don't have access to a vise, you have to make sure you place the receiver on something that doesn't absorb impact energy. You need the force of the hammer and punch to transfer into the pin solidly. Without clamping it as above, you also introduce an off-axis force that wants to turn over the receiver with every hit.

Good luck.