I agree on the barrel and ammo and how good old guns can be; here's my 2 cents, even if they are not single shots---
Even today the gun mags seem to think 1" at 100 yds (1 MOA) is the Holy Grail of centerfire off the shelf bolt guns costing up to $2000 or so. Usually with a $500 scope on it too. Admittedly usually 5 groups of 5 shots or so but usually the writer tries to cook up some handloads for better accuracy too.
So, my first Savage 99 lever action--1953 vintage I bought 2 years ago, I took to the range the first time. It was a 99EG, with an older Simmons 3X9X32mm scope. First box of ammo was Rem. factory, and groups were 1 1/4" after sighting in-not bad I thought considering my skills and a lever gun. Second box of ammo was Federal Premium 150 gr. Voila! .7" groups all that day and other days!.
Sold the gun a year later in a moment of weakness even though I thought I had one remarkably lucky and accurate gun.
Got the Savage 99 bug again, and bought another one 3 months ago--same exact model gun also in 300 Savage except made in 1954 (still over 55 years old)
This time, shooting with an old Japan made Tasco 2.75X40mm Turkey / brush gun scope on it but same ammo.
Guess what? .7" groups again! Here's a pic of the 1953 gun and target--only had a SB target
(You need to Login or Register to view media files and links) (You need to Login or Register to view media files and links) These guns were stock too--only thing I ever did to either of them was REALLY get all the old copper fouling out of the barrels with WipeOut and then about 3 sessions with JB Bore Paste.
Someday I'll wring out my old Stevens 418 22LR for a day to see what it will do at 50 yds with different ammo's too. Right now I am at 1 1/4" and an occasional 1" at 50 yds with it, using CCI SV and Wolf MT ammo and the stock iron sights (Lyman 17A front with a lollipop insert and Lyman 48L or Lyman 144 rear sights)
Will keep you guys posted when