that can shoot sub moa without much work needing to be done.
Any service rifle, given enough ammo through the barrel, just by statistical variance, will shoot one sub MOA cluster.
We see these targets and claims all the time by guys who don't show us the huge target spreads they normally get.
Service rifles are not sub MOA. They were never built to that standard. The M14 had to shoot ball ammo within 3.5 inches. The 50’s NM Garands were acceptable if they shot within 3.5 inches at 100 yards. An M1 Carbine won’t stay on a pie pan at 100 yards.
What I have read is that the average service rifle accuracy requirement was close to 3 MOA. The military looked at average engagement distances, the size of the target, how long the target was visible, and 3 MOA is reasonable.
My AK and SKS’s are 8 moa at best.
You will not find a sub MOA rifle for the price of a military surplus rifle. Sorry.
Of the military surplus rifles I have owned, pre WWI Mauser 98's in 7 mm Mauser were very accurate, the Swedish service rifles are very good, and the K31 is very good. A M1903A3 is very good, given a good barrel and bedding.
You take any one of these relics to a 100 yard high power match and the best you will do is win Marksman class.
You are not going to shoot a HM score.