RE: Help- Ruger M77- 7mm
Ruger 77 with a 4200 elite on top? Nice rig. Haveone myself.
I'm assuming it's a 7mm remington mag and not a 7mm-08. Some might feel that the 7 mag is too big for deer, but I like it. It's a flat shooting, hard hitting round and it should be able to take down just about everything in North America shy of grizzly/brown bears.
Maybe try different brands (and bullet weights) to see what your gun likes best. Pretty much any weight offered in 7 mag will take down deer, though. I shoot reloads in mine, but prior to that I always had good luck with Federal.I really like Hornady ammo, though.