Ruger m77 mk ii

[bamaranger]

MkII's

Somebody said it earlier, but I'd be darn sure that the rifle is clean, as in bare bore and not copper fouled. The new foaming cleaners are pretty good at removing copper fouling, as long as they are intended to do so in the first place by the manufacturer. A foam treatment ( I usually do two) may prove that one's clean bore is not so clean after all.

I have also read somewhere, recently (likely on these forums) that the torque spec's for the diagonal bedding screw in the M77mkII are quite high. You might try getting a torque wrench and experimenting with different degrees of tight on the bedding screw. I'd likely do that with the best performing ammo you've found thus far.

There is also the whole issue with Ruger "contract barrels" early in the MkII history, and Ruger long throats. Seems like there's a thread running right now regards those points.

Honestly, 1.5MOA from a plain vanilla factory sporter with factory ammo is not particularly poor, more like about average.

 

[mehavey]

I can't remember the exact formula the best accuracy load was 75 gr vmax but I prefer a heavier bullet.

Heavy bullets are just a "bit" unstable in the Ruger twist when run at "lower" speeds

87 grainers at normal speeds, however, are <½"

QUESTION: How fast is the OP running?

 

[Lwh4207]

Mehavey what is lower speeds? According to my manual I should be doing around 2950 for 100 gr hornadys

 

[Lwh4207]

Mehavey what is lower speeds? According to my manual I should be doing around 2950 for 100 gr hornadys ,but I don't have a chronograph so I can't verify that

 

[mehavey]

The pic above was deliberately baselined at about 100gr/2,500fps (for fun purposes.)
If you're 400-500 fps above that, things should be OK.

 

[brasscollector]

Besides the 75 gr vmax I have had better luck with the heavy bullets I'd like to try the 95 gr sst

My 243 (not an M77 however) would not group the little boat tails at all. 1-1/2" was the best I could do with the 58gr and 75gr v-maxs. Soft-pointed boat tail hunting bullets of 80gr and 100gr also didn't fare very well. I was losing hope. Finally tried some 95gr SSTs because they were flat-based (friends advice). I had all the little stacked-up groups I could shoot. I didn't measure all the groups but the ones I did were in the 5/8" - 3/4" range which I was happy with.

 

[Lwh4207]

I'm a pretty big fan of the sst bullets they have performed outstanding in the calibers I use them in ,but I havnt had a chance to load any up for my 243 yet.

 

[dvdcrr]

The only bullet I tried which was too long was a Swift Scirroco (95 gr.?)

 

[Mac11]

Another trick to try on a Ruger M77 is to open the magazine trap door and see if the mag sleeve will move just slightly with finger pressure. There needs to be some movement to ensure the action isn't being pulled down on the mag sleeve and causing some distortion of the action when it's torqued to 90 in/lbs. Both of my M77s were tight and it's not uncommon that this one little thing will correct a poor shooting rifle. Generally this will render better results than a pillar bedding job. On the bottom side of the sleeve, not the action side, Using a HAND FILE, at the contact point of the the trigger guard in back and the trap door hinge in front, remove just enough metal to get the sleeve free front and back when the action is reassembled, usually only a couple of thou/ in. More is NOT better and you may need two or three tries to get it right. Takes 15 minutes to accomplish. Worked for me on a 6mm and an '06, it may work for you.