I have had a Ruger M77 MKII since 2003 chambered in 260 Rem. It has been an interesting journey getting it to shoot, as I am sure some of you other M77 owners know! I had put the gun in a Boyd's laminate stock several years ago, but accuracy was still sporadic at best. Finally started chasing down several things. Started by free floating the barrel, and getting someone to bed the stock. Accuracy was still hit or miss. Finally started really looking at the magazine box. Discovered that the inletting on the Boyd's stock was binding the magazine box keeping it from seating properly, this putting a lot of pressure upwards on the action. Went to work with a file and some cardboard ( to shim up the one spot that was too low.
Got so e Sierra 140 match kings, and 139 Lapua Scenars. Now the gun that shot a lot of 2-4 inch groups shoots mostly 1-2 with some better. A few weeks ago found a load that shot .8 with the Sierra's. Took it out today with the Scenars and it shot .64 4 shot group at 100 yards! I am not a bench rest guy, and need to learn a lot about shoot, but that made me really happy! Finally feels like a gun worth keeping, and can't wait to start stretching the Scenars out to 500 yards.

Make me want to go tinker with my Rugers

That's the first thing I do to mine. They are all tinkered out. Shoot great after a couple hours of work. Easy enough.. If you are not familiar with them, or not mechanically minded, I could see how guys could have issues.

Jevyod, by seating the magazine properly I'm not sure what you meant. Are you saying that you have the mag box seated against the receiver? If that's the case it needs to be free floated just a tad and I promise you your rifle will shoot better. You should be able to reach in with your fingers and the box should have just a touch of freeplay. I wish the best to you on your project. It's always fun wringing out the true potential of any rifle

Edited to say I didn't see that you shot .64 group. If it stays consistent I wouldn't worry about it however if accuracy is sporadic I would float the mag box

I am neither mechanically minded nor ever had a shop like some of you guys (BSA) As a pastor, I had to prioritize my Time/Involvement to my Rifles. I have always been able to find good gunsmiths to do that for, the tweaking. I know what I want the rifle to do, and, with Mod 77 Tangers, Ruger No 1's, the occasional MK II or Hawkeye, have all of them ,for me, needed tweaking, ha.
I think I like the Hawkeye SS Synthetic "All Weather" the best of them all. Last year I bought a 1S Medium in 300WM (that I shoot well in bolt guns) was too uncomfortable in recoil for me, maybe its my old shoulder now too. Ruger 77s of any make are definitely "rugged Tanks" though! Enjoy your rifle Pard, you are "there"!

Jevyod: I am so happy for you getting that Ruger to perk up so well!
My first 260 Remington (Remington 700 VLS - Varmint Laminated Stock) shot wonderfully well, from day one.
I assume your Rifle is the sporter weight barrel?
The 260 Remington cartridge is a versatile and accurate round in my experience.
I hope you put that Ruger 77 to a lot of use now.
Again good for you.
Hold into the wind
VarmintGuy

Good job Jevyod. I have two Ruger 270's, a tanger and a mk II. Both needed work, the key was the mag box. Both went from 2 in. groups to moa or under with my reloads.

I am a mechanical klutz but still manage to trim the magazine box on my Ruger M77 rifles. It has helped the accuracy of all troublesome Rugers M77s I have owned, some more than others. Ironically, one of the best shooting rifles I own is a synthetic stocked M77 MKII 308 stainless with the magazine box unaltered, barrel not free floated etc. It shoots .5 moa groups with several different loads.