Was working on an AR upper and it fell off my work bench and hit my garage floor. Dinged the edge of the block the pivot pin passes through and crushed it enough that I can get the pivot pin 2/3 of the way through but then hit heavy resistance. I was able to drive it through with a spare pin and punch but I don’t want to be hammering my upper off and on lowers whenever I need to clean it. I tried driving the pin through a couple times in each direction but it is still malformed enough that isn’t a great solution. Anybody dealt with that before? My brother said a reamer would probably be needed to fix it.

It’s a 1/4” hole so you can try a 1/4” drill bit.
A reamer would work also.

You could try and drill it out a little, it shouldn't take much. There's also replacement takedown pins you could get that make pulling the rear pin out easier with a ring or paracord pull on it.

Use a reamer, not a drill bit.

And I little drop of A9 for lube.

If you can take a picture of the affected area. Even a reamer might be too much. Tolerance for the hole should be .250-.251 you go too much then if becomes a wobbling, useless monster. you might get away with a littler emery cloth or fine grit sandpaper in just the affected area.

Thanks for all the feedback everyone. Attached are the photos. It is a Gibbz side charging upper so not thrilled I let it pop off my workbench. I think it is beyond a little sanding. I tried a file just a small amount on the dinged end with little improvement. To get the pin through I have to drive it with a hammer and pin punch. I did that about two times from each side to see if that pushed it back into shape using a spare pin I had. I mean helped a small amount but not much. Seems a bit crushed on the damaged end. Based on the pics would a 1/4" reamer be the way to go in this situation? Do I need a drill press or would I be able to do it with a hand drill? I did contact Gibbz so maybe they will let me send it in to them to fix.

Well, personally…

Put the pin in and let it be. It doesn’t impair function. You can still take down (shotgun) the AR and clean and do all the things. It’s structurally sound. It’s definitely cosmetic.

I wouldn’t spend money on repair but that’s me. You dropped it. Life goes on. But if you have the money and it bothers you that it got a ding. Then spend away.

Me - buy more mags and ammo with money not spent on repairing cosmetic issue???

But my perspective is that firearms are tools. Sometime pretty but used… and abused by use. FYI - I have broken more guns than most own. (Fortunately for me most have been under warranty so got them fixed pretty cheap/free).

This appears to be the front pin? If so, put it together and leave the front pin in place, just remove the rear pin for cleaning.

Any attempt to open up the hole will probably be futile, the hole is now oblong and fits tight on one side, removing that material will make it loose on all sides

On another note if that is your designated gun cleaning/building/maintenance area put down a rubber mat. It will help your back and save these type of stories for the other guys.

Good Luck

If that were my gun, I'd rather MOVE material, than REmove with drill bit or reamer.

I'd either use a tapered punch to widen the hole back out, or (more likely) just pound the pivot pin back in and leave it.

While I sometimes remove upper from lower for a thorough cleaning, not being able to do so would'nt be a deal breaker, for me.

As someone who's paid to drill holes in aluminum, I would only drill or ream as a last resort. You'll probably end up with a sloppy oversized mess. I like Vin's idea of using a taper punch to recircularize the hole. Be gentle though, the alloys used in AR receivers are not very ductile and will crack if bent too much. Instead of reaming, I would use a fine tooth round file to return the hole to round. File a little and test fit often until you get a satisfactory fit. You'll need to file smooth the dents and gouges on the outside where it hit the floor to remove stress rises which could form cracks.

Doesn't look too deformed. You might get away with cleaning it up a little with fine sand paper or a stone. Just remove the jagged edges and nothing else then touch it up with a sharpie.

Smallest chainsaw file you can buy.

DONT drill it. DONT ream it.

The drill and the ream will take material off the smashed side AND the side 180 degrees from it as the drill/ream tries to center itself into the "newly tightened" opening. The resulting hole will be sloppy and offcenter/misaligned.

Take the chainsaw file and barely draw it across the smashed side/edge until the pin just passes thru snugly.

Check it between EVERY file stroke.

This is exactly my thoughts...shouldn't take more than a few light strokes to clean it up.

Gotta love how loggers think...