I just purchased an all weather Ruger M77 MarkII in 7mm Rem Mag. The gun currently groups 1.5" at 100 yds with 140 gr. Nosler Ballistic tips. I am intersted in swapping the stock for a drop in mcmillan that is from cabelas ($359). Does anyone have any experience with this stock or can you recommend a good drop in alternate? Should i expect improved accuracy if I change the stock?

McMilain make good stocks,but for 1/2 the money I would look at the Houge with pilar bedding.
If not I would also look at Boyds wood stocks.
As for accuracy bedding might help,also I would look at a diffrent bullet.

No guarantee that a replacement will make the gun shoot any better.. I had that model rifle in same caliber last year and it shot very well with plain 140 grain corelockts. I adjusted the trigger and that was it. Bedding on mine was tight thru the barrel channel and didn't seem to be a hindrance at all. If you absolutely do not like the stock then I would suggest a Mcmillan. Hogue stocks are heavier then McMillan stocks and the factory stock as well.

just a quick note, my buddy bought a "drop in" Boyds stock, for his m77 at half the price of others, but it wasnt 100% drop in, some fitting had to be done by our smith. I think he got it for $120?

Yeah you can get semi-inleted,wich reqirue some hand fitting,but also you can buy them finished.

I have several Ruger rifles I personally prefer the Bell&Carlson stocks Cabelas has them for 160.00 .

I would go with a H-S Precision stock. Go to http://www.hsprecision.com/pss20.htm Good luck.

Why would you replace the stock, is it to customize it yourself, or do the aftermarket stocks improve accuracy?