I bought both new,a Ruger M77 Mark II and Nikon 3 X 9 Prostaff. The best pattern at 100 yards is a 6" group. At the range yesterday, all went well with the other guns I shot. I even tried a lead sled. I don't have a spare scope right now or I'd swap scopes and try again. The question is, anyone else using the same set up with or without issues????

I am sure there are tons of people using the setup without issues. Without changing a variable you'll never narrow down the problem.
Different ammo, different scope, different base rings.

First make sure your bases and rings are all tight, not wobbling. My groups opened up one time while I was at the range, check the rings, they had come loose. I use Loctite after that.

Ammo after ensuring everything is locked down tight. Last of all, try a new scope when you have one available.

Assuming that all the screws are tight, it sounds like you got a lemon of a scope. Although I've never had any issues with my Nikon scopes I suppose there's always an exception. It could be that the reticules have come lose. Nikon has an excellent service and I'm sure they'll send you a new one, but if it were me I'd take it back to the seller and get another one.

While at the range yesterday, I did check the mounts and rings.
Should I change ammo and shoot again or try a different scope.
I believe it's best to change only one thing at a time to find the culprit.
Using Remington factory ammo130 gr psp.

First thing I would do is clean the heck out of the bore (copper fouling can be a real problem for accuracy). Get a good copper remover like Barnes CR-10. Now try the same ammo again.

If that dont work then clean and change ammo and try again.

Next I would look real hard at the rings. I had a brand new M77 with rings that would not hold the scope in place. Every time I would shoot the scope would slip in the the rings. It turned out the top of the rings were bottoming out on the lower part of the rings before they were tight enough. I got a new set and no more problems.

My next step would be to swap scopes.

After all that it only leaves the gun it self.

After you check the scope mount screws check the screws on the rifle itself. It doesn't take much for a loose screw to make life miserable. I am not familiar with Ruger 77's but I am sure there is at least 1 or 2 that hold the stock to the barreled action. Good luck

i had a cheap syn stock causing same prblm on a 300 wsm..

Just askin, did you clean the oil out of the base screws? Did you use lock tite on the base screws? Did you torque (again, base screws) then till your hand hurt? If not, pull the whole sucker apart and do that first.

Check the guard screws that hold the action to the stock.

I had a Nikon Buckmaster on my rem model7 in 7mm-08. Went through 2 boxes of shells trying to sight it in. Even paid therangmaster to try for me, ended up I had a bad scope. After I got that replaced by the vendor that sold it to me, it shoots like a dream.

Thanks for all the input!
When I flipped it upside down, I found three screws. All were firm but I was able to tighten two almost a full round.
I have not ever applied lock tite on gun screws. Do alot of you "lock tite" your screws?
The barrel is MUCH thinner than on all of my Remington's 700's.
Could the "thin" barrel be a coutributing factor?
The gun is Stainless and composite...

There are certain torques the screws on the bottom should be set to.

I've never found a decent Ruger 77.

Haven't looked have you?

I have probably owned more Rugers than any other brand and I havent found a bad one yet.

Ruger had a time when their barrels were not noted good for anything except as a tomato stake.
Trigger has usually been lawyer proof, so some mods were warranted.

You have Savage and Ruger confused!

I had same problem with same scope of a new 300 wsm i bought took scope back and put new one on, shoots like a dream now.

Only scope problems I had was from the people at bass pro installing it. They did a crap job 3 times in a row. I now own the tools to do it myself and doubt I'll ever have someone else do it again. A 1 pc railed base is the way to go.

I have been told that locktite is bad juju,

because if you want to remove the rings or mounts, you might strip the heads and have to take it to a gunsmith to drill out.


I was taught to use a drop of gun oil on the bolts ( the oil thickens and helps hold the bolt in) and to torque to where a 3 or 4 inch allen wrench will start to flex a little with the pressure at the end. I would guess around 26 ft lbs.

I did this and have shot 100 rounds out of my new rifle this month with no bolts loosening or zero shift. I checked every 20 rounds and never needed to tighten them.

I also have a 1 piece scope base from DNZ.