Weirdest thing happened to me yesterday while shooting my Ruger 10/22 and I am not sure what it was. I was shooting and everything was fine then on one shot when It fired the rear of the scope mount popped off bending the base slightly. I really wish I took a photo before I took the scope off but I wanted to remove it right away to prevent damage to the front 2 screws that were were still holding it on but the mount was bent I was able to screw the screws back in and they holding.

I double checked to make sure the rings were the same height with a micrometer and they were and there was no problem installing the scope and I have done may enough to be a pro at it and It sighted in fine and has shot fine other than an occasional feed issue with certain brands of ammo. I also noticed that the trigger group was wobbly I never noticed this before and I took it apart and noticed that the left side was slightly bowed.

I was using some really old Blazer ammo which out of the same 500 rd. batch I have had 2 rims blow off while shooting them in a AR22 which I dismissed it as just feed issues.

It seems like it would take a tremendous force to pop 2 screws out of a receiver and hard enough to actually bend a aluminum scope base.

Weird. Check the unloaded barrel to make sure there is no obstruction.

Strange.  If it was an oob discharge, I would have expected damage to be at the front.

I won the Winchester ammunition quality control lottery and had a round of double-charged .22 explode in a 10/22.  It blew the magazine to bits all over my feet and the extractor utterly disappeared, but otherwise the receiver was sound and I don't remember any other issues.

No obstruction.

That is my thought but its all fine in front and the BX25 mag is fine. Is there even enough pressure say if it was an oob that if it blew out on the left side that the pressure could have been funneled to the left and trapped in a way that it popped out the 2 rear screws out and put a slight bend in the scope base.

I can't say for certain that the bow on the left side happened because of this or if it was there to begin with because it may have been something I never noticed before although I think I would have noticed the wobbly trigger group because of it.

Or maybe another thought if it was an over charge case that it may have slammed back so hard that forced air pressure popped them out I know that sounds like grasping.

My first thought was somehow a round got behind the bolt and managed to go off but that would be impossible.

Just swinging blindly here but could the mount screw have somehow protruded too far into the receiver got into the path of the bolt?

I know that is a LOONG shot but the only thing that comes to my feeble mind

OP, I think it just depends on where the case head blew out.  In your case, sounds like it was at the worst possible spot.

I agree with Makarov, take a look at the top of your bolt and see if there are any impact marks.

That's a good guess but the screws do not protrude at all. There are a just below the surface. No marks at on on top of the bolt

If a screw popped out, surely some threads are stripped somewhere.

Oddly I was able to tighten them back up but I am sure they are not as good as they were and will probably need to use locktite or tap them for a wider screw to make sure they are secure. The front 2 screws held tight just the 2 in the rear blew out. I know I had problems with that ammo doing that with the AR22 blew the case head off leaving the case stuck body in the barrel. There was no case left in the barrel of the Ruger though.

I am going to have to assume somehow there was enough pressure from a oob or maybe over pressured round managed to funnel its way back to blow out them screw and bend the base. It still amazes me that a tiny round like a .22 rimfire could do that. I know that it could but not like that with what I would consider plenty of other directions for the pressure to go.