A member of another forum recently posted that his M1917 had only been capable of 4-5 inch groups using modern sporting .30/06 loads but when he ran across some 1939 Franklin Arsenal headstamped ammo he got 1 inch groups.

Near as I can figure that ammo used the 152 grain soft lead core bullet at around 2,800 + FPS, they'd raised velocity by about 100 FPS starting in 1936.

He said the bullets were silvery looking but I think these were the gilding metal bullets with jackets treated with stanic acid to give a silered look, to avoid mixing them with the heavier MG loads with untreated gilding metal jackets.

Rifles can be highly individualistic in which ammo they handle best. Thats why I much prefer to taylor handloads for each rifle even if I have several in the same chambering.