Home Forums Hunting & Shooting Rimfires Shimming 77/22s is a real thing!

Last summer my 12 year old saved his chore and odd job money to buy himself an all weather 77/22 since he liked how it functioned just like his Model 70. I inherited a first year production blued model which has been stellar so I certainly encouraged his purchase. We took various loads for sight in to see what his rifle preferred, which was in a word, nothing. The thing shot 3-4 inch patterns at 50 yards. Trying to convince himself, he asked "That's not too bad is it?" To which replied "No, this totally sucks." We had a dejected kid, the .22 went to solitary confinement, and life moved on for while. During the winter doldrums I researched, bought, and installed one of these shim kits, and the other day we shot the same ammo.

This gun now shoots everything we have acceptably and some stuff excellently. Groups with eight different loads went from 3-4 inches to 1-.5 at 50. Federal's American Eagle 38 gr HP went from one of the worst shooters to one of the best.

All of which is to say if I every come across a cheap 77/22 which "won't shoot" I'm gonna buy it and try this shim business again. Has shimming worked this well for anyone else?

Mine were in the mail on Saturday and I’m about to put them in. Did you try different thicknesses and how did you know that you got the right thickness put in?

What part of the rifle ae you shimming....trigger, action, stock?

My 77/22 shoots pretty well, but I'm always open to improvement.

The bolt on mine. I just measured the gap between the front and back half of the bolt at .028” and that seems excessive to me.

Use the thickest shim that will still allow the bolt to open and close without excessive force. If the bolt is too difficult to operate use the next thinnest shim.

What he said

I did something similar to a Marlin 880, brass shim stock. Groups shrunk and got round.

My buddy was wanting to try this with a Marlin after our results. Did you buy them or make them?

The 2-piece bolt body.

I shimmed my 77/22 a few years ago. It's accuracy improved and with the right lot of green tag, it'll shoot under a moa at 100 yards.

Triggershims.com, out of Michigan, offers some great stuff and a wealth of knowledge/experience.

Shimmed my 77/357. Reduced group size with most ammo by about an inch.

Connecticut Precision Chambering specializes in shimming 77/22 bolts and doing trigger jobs and muzzle crowns. Also does similar work on 10/22's. I bought a 77/22 Hornet about 10 years ago and sent it to them for rechambering to 22K Hornet and got the full accuracy package--all for $225 with a two week turnaround. They have a good website. Cant recommend them enough.

I had a 77/22 mag that really wasn't pleasing me so I changed it to a 77/17 Hmr with a Green Mtn barrel before learning about the shim trick. The .17 was very accurate anyway but I went ahead and shimmed it. Couldn't really tell any difference. I have wondered several time if I would have been able to tell a difference if I had switched it back to a .22 mag.

Straight forward installation. Be sure you turn the shroud clockwise, per instructions, when taking it apart and not counter clockwise. People do make there own shims but as stated above they are for sale.

I purchased and just put mine in but have not shot yet.

For sale:

https://www.triggershims.com/ruger_m77.php


Install Video:

https://www.youtube.com/watch?v=0CmRPQ4h9uM

Thanks for the links, ned.

Agree. I'd had CPC do the bolt shim package on my 77/22 quite a few years ago mainly because people at Rimfire Central were reporting good success.

My 77/22 shot fine before the bolt shim, but I was curious. Groups did shrink even more after the shim. I shot test groups before sending off and did them again when I got the rifle back using the same carton of varmint ammo.

I have shimmed mine and it is way better for sure.

It’s a pity that one has to do this to make a new rifle shoot decent.
I have a Ruger 17 hornet. It shot poorly, 2” at 100 yards on a good day. That’s with lots of load development, different powders and bullets.
I shimmed the bolt, put in a trigger kit to go from over 5 pounds to just under 3 pounds, glass bedded it and it now shoots about 1.25” groups.
Lots of extra work and cost to get a a Ruger to even have fair accuracy.

This is true. As the saying goes you can put several hundred $ into a 77/22 and it will still not shoot as well as CZ 452 22lr out of the box costing less than a 77/22. No need to wonder how I know.

I do have fun with my 77/22. Putting a Green Mountain barrel on made a huge difference. It will be interesting to see if the shims make a difference.