77/22 octagon Green Mountain barrel? - RimfireCentral.com Forums

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Old 05-15-2019, 10:02 PM
Model 52
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77/22 octagon Green Mountain barrel?



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I purchased a first year of production 77/22 recently and noted the accuracy was around 2 MOA at 50 yards.



I replaced the sear and trigger spring, then shimmed the bolt and I still found the accuracy was in the 2 MOA range.

The other night I free floated the barrel and today I found it is shooting much better:



Free floating the barrel without bedding the action is something of a tail chasing process as eliminating one high spot lowers the barrel on to another in the fore end or just in front of the chamber. However, my initial efforts were sufficient to suggest I don't necessarily need to rebarrel it. I'll bed the action and see how it shoots again this weekend.


------

That said, I am still potentially interested in the 24" GM octagon barrel. However, I have not been able to find any pictures to see how it actually looks in the standard barrel channel. Does anyone have one, and could you post pictures?
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Old 05-16-2019, 05:25 AM
azimuth

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Nice looking rifle!
I also have one of the first year models identical to yours and it shoots right at moa at 50 yards. I haven't tried it any further than that. Yours seems to be shooting quite well, now. Don't know anything about those barrels. I do have one on a 10/22 that shoots quite well. Do you have a link to the site where they're being sold?
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Old 05-16-2019, 09:34 AM
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Guess I should have floated my barrel instead of buying a $250 Shilen?
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Old 05-21-2019, 10:00 PM
Model 52
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I glass bedded it this evening.

I noted the stock had more or less typical Ruger bedding with 4 points out near the corners that support the action (easy to mill the stock in 1 or 2 horizontal planes for a reasonable fit to the action), plus the tang. I bedded it accordingly and we'll see how it shoots Thursday or Friday.
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Old 05-22-2019, 08:32 PM
Model 52
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It's out of the stock and bedding is cleaned up and ready to go. It's nicely free floated and the bedding should hopefully eliminate the remaining fliers.

The cat approves of the bedding color, but she isn't overly impressed with the rifle itself. She's a CZ fan and has given up on the 77/22. I'm still hopeful it can be turned into a consistent 1 MOA 5 shot group rifle.

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Old 05-23-2019, 10:20 PM
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I'm going to declare the bedding job a success.

50 yards, 5 shots with SK Std Plus:



Not quite in there with my CZ 453's and CZ 455, but not enough to matter for any practical shooting.
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Old 05-30-2019, 10:35 PM
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I sanded the barrel channel a bit more to free float it enough to clear a business card, then sealed the stock and took it back to the range.

I also shimmed the rear of the firing pin by .017" and resolved the occasional light strike issue.

I'm satisfied with it's performance.

Just to recap, it started here:

25 Yard group:



Improved a bit with shimming the bolt:

50 yard group:



Improved a bit more with less vertical stringing after free floating the barrel:



And eliminated the fliers after bedding the action.



An improvement from about 3 MOA at 25 yards to about 1.5 MOA at 50 yards.
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Old 05-31-2019, 10:57 AM
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Nicely done!!
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Old 05-31-2019, 06:06 PM
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Looks like those groups are really tightening up!

Quote:
I also shimmed the rear of the firing pin by .017" and resolved the occasional light strike issue.
Would you mind sharing a little bit of detail on how you shimmed the firing pin? I get occasional light strikes that I would love to eliminate. These early models don't take to kindly to extracting unfired rounds.
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Old 06-10-2019, 04:51 PM
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GM barrels

I live about 40 minutes or less from GM's retail store. They have a scratch and dent room. Barrels have some cosmetic issues, though most are really hard to see. They have no issues with the bore, though. A while back they had a .17 barrel for about $75. Though the barrels look very similar to the 1022 there are some small differences which make them not worth getting for the 1022, otherwise, that barrel would have come home with me. These barrels are only available in store, they are not advertised on their website
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Old 06-12-2019, 09:12 PM
Model 52
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Quote:
Originally Posted by azimuth View Post
Looks like those groups are really tightening up!



Would you mind sharing a little bit of detail on how you shimmed the firing pin? I get occasional light strikes that I would love to eliminate. These early models don't take to kindly to extracting unfired rounds.
I had occasional light strikes, more frequent with some brands than others and I noted that the rounds always almost never fired when cycled through the rifle again, but always fired in any of my other .22 LR rifles. Looking at the firing pin impression in the failed to fire rims, it was apparent the firing pin protrusion was no longer adequate.

The firing pin itself has a semi circular base with the pin attached to the middle of the curved portion of the semi-circle. The flat side of the semi-circle aligns with a slot in the front of the rear half of the bolt.

I noted there was about .002" of play in the slot with the firing pin inserted, and but I also noted the impressions needed to be deeper to get reliable function. I opted to increase the firing pin protrusion by .017" to get firing pin impression depths similar to my other .22 LRs, while still ensuring it did not extend past the outer edge of the bolt face (since you do not want the pin to damage the face of the chamber if the rifle is accidentally dry fired).

I did this by removing metal from the front face of the semi-circular base of the firing pin below the firing pin shaft. Since my mill (and lathe) are still in NC, I did the work with very careful application of a flat file. You need to take care to keep the face square and even as the pin will come to rest on that face when it is fired and you need it to come to rest evenly to avoid stressing the pin.

Once I removed enough metal to get sufficient clearance in the slot, I installed a .017" piece of shim stock behind the firing pin. I cut the shim from a .017" feeler gauge, shaped it, installed it, and re-assembled the bolt.

It's been 100% reliable since.

-----

Provided you take care to ensure the pin doesn't protrude far enough to impact the chamber face, there's not much to lose in shimming the pin. Starting with a new pin and shortening the pointy end to get proper protrusion would be a lot easier, but of course Ruger won't sell you a pin, you have to send the whole rifle back, and they have a bad habit of returning them to stock condition before they send them back. They must have a warehouse full of Volquartsen and Timney triggers along with bolt shims and other aftermarket parts they have removed.
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Old 06-13-2019, 11:19 PM
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Model 52... Been many of years since I had to shim behind the firing pin... Even then it was .003" - .005" shim no filing...
Most complaints of short firing pins are rifles with excessive headspace... Close the headspace by .005" - .008" down to .041" - .043 headspace for example .22 L.R. and its the same as extending the firing pin by the .005" - .008"....
Now what I never understand is HOW the Ruger 77 firing pin is made... Can not figure out if its one part or two...? Been a total mystery to me for years.... Must be a mystery to all others of how they are made because I never seen a aftermarket 77 firing pin....
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Last edited by CPC; 06-13-2019 at 11:23 PM.
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Old 06-16-2019, 04:33 AM
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Thanks for the info, Model 52
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Old 06-16-2019, 11:48 AM
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Quote:
Originally Posted by CPC View Post
Model 52... Been many of years since I had to shim behind the firing pin... Even then it was .003" - .005" shim no filing...
Most complaints of short firing pins are rifles with excessive headspace... Close the headspace by .005" - .008" down to .041" - .043 headspace for example .22 L.R. and its the same as extending the firing pin by the .005" - .008"....
Now what I never understand is HOW the Ruger 77 firing pin is made... Can not figure out if its one part or two...? Been a total mystery to me for years.... Must be a mystery to all others of how they are made because I never seen a aftermarket 77 firing pin....
I shimmed the bolt to minimum clearance and that .007" didn't help matters in terms of light strikes. Turning the shoulder on the barrel to set it back and then recutting the chamber would have been an option instead that would have also shortened the reach for the firing pin. This is where "drop in" replacement can cause issues with light strikes. In any case, we're still in between houses and my lathe is still in NC, and even if the lather were here, it would have also not been a 10 minute job.

The other option would have been to use a TIG welder to extend the tip slightly and then reshape and fit the firing pin. The downside is the potential hardness of the tip. I'm not sure what Ruger uses for steel and or heat treating and hardness. To soft and it won't last, to hard and you run the risk of breaking the tip.

Consequently I opted for a simple approach, addressing the issue directly (and quickly) to increase the firing pin reach, since I didn't feel like sending the whole rifle back to Ruger. Rather than look for a minimum protrusion that worked, I opted for maximum protrusion that would not damage the face of the chamber. One and done.

Last edited by Model 52; 06-16-2019 at 11:53 AM.
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Old 06-16-2019, 12:45 PM
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That's great work on your 77/22. Fantastic shooting as well.

I was not so lucky on mine - and it got a new barrel. Fixed it right up and took me to the point that other fixes actually did something. Prior - my work on bedding, shimming the bolt, trigger basically got me nothing.

As you found on yours - mine responded EXTREMELY well to bedding. I bedded mine like yours but adding about 3" up the barrel from the receiver. The rest is floated.
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