Here we go:
Left to right: Ruger MKII PF, .22-.250, Ruger MKII PF, .22-.250, Ruger MKII LA, 6mm AI, Ruger MKII SA, .20P. When the Ruger M77, MKII first came out it was a push feed. Non rotating Mauser type extractor but designed to pop over cartridge rim.
This makes for a nice single shot rifle having a strong stock without the usual magazine . Observe the Timney trigger, set at 2 pounds, a drilled & tapped hole behind the recoil lug, same size as used on Rem 700's, .25 X 28, & the enclosed bolt face, push feed only. The .22-.250 with the maple stock is also a push feed M77 MKII having the same workings.
Ruger M77 MKII rifles with their investment cast receivers can be a challenge for scope mounting. I have used the Burris Ruger adapter with Burris Signature rings to mount scopes for long range use & to keep reticle near center. Old 1 " tube scopes on the .22-.250 PF's, have been replaced with Vortex 6-24X50 PST & 6.5-20X50 Leupold VXIII 30 mm tube scopes, mounted with Burris Sig rings & Burris Ruger base.
Scope mounting details: Burris Ruger clamp-on bases & Burris Sig 30mm rings were used to mount this Vortex 6-24X50 PST on wifey's .22-.250. This allowed a mount where the reticle was centered.
By luck, these lapped Ruger rings allowed a mount on the 6mm AI for this Burris 5-25X50 with the reticle centered. A pic showing a 87 VMax crater on 1 3/4 diameter mild steel hit at 300 yards with the 6mm AI, MV 3475 fps. Despite the modest G1 BC of .4 the 87 Vmax at 3475, 10 twist does real well on 1/2 gallon milk carton size rodents up to 1/2 mile away. No ice pick VLD effects.