This was my CZ 457 in .22 mag - pics below. Sheared from bolts holding it in place. Happened after the first two 5-shot groups of the day. Cut the range time short big time. Went home, got online and ordered a metal replacement from D.I.P. Had to replace the firing spring over a year ago as well. Round count is over 2K. Lilja barrel - still shoots great.
UPDATE:
New magazine well arrived yesterday - 3 days - probably a record for 1st Class Mail from ID to FL!
I installed it today no issues and it fits and works great.
That said I found another issue. I took the stock off and although it is not necessary to the take the rear magazine well screw completely off, I did it because I wanted to make sure there were no small plastic pieces anywhere. I did find some.
And, I also discovered a big problem. There was a lot of barrel cleaning fluids in there full of gunk and crap, and even worse the bottom part of the bolt guide was awful. The bolt guide is the stainless piece that is held in place by the rear magazine well screw.
I removed the bolt guide - now loose inside the action (it's part #31 in the CZ 457 manual) and it was not only covered in fluid and gunk, the bottom had corrosion on it too - a lot of it.
So, I took it to the sink and let it sit in degreaser for a while. Then cleaned it with a blue abrasive sponge and rinsed and dried it. That didn't do anything for the corrosion so I took that off by wet sanding it with 320 grit.
It still has some marks on it but it is clean and fully functional with no corrosion.
I guess this is a problem with a number of rimfire rifles. The bore cleaning rod guide is open on the bottom and all the liquids just fall in there on the stainless bolt guide and from there into the magazine well - it make a mess! I'm now wondering if the bore cleaners weakened the plastic magazine....
I clean my rifle every time I use it (.22 MAG is like a centerfire in terms of copper, etc.. That's a lot of bore cleaning fluids going in there over time. Next time I clean it I'm going to put some Blue painter's tape all in there, or some Saran Wrap and then insert the bore cleaning rod guide to try to keep all the fluids out of there.
Will report back when I see if it works!
