Home Forums Hunting & Shooting Hunting Rifles Identify Scope Mount for Springfield 1903

Gentlemen,
I have a Springfield 1903 rifle in a sporter stock. Once upon a time it plainly had a side mount, which was mounted on three holes drilled into the left hand receiver wall.
The rifle shoots very well indeed with the open sights on it, but unfortunately I have decided the straight stock design does not suit open sights shooting (which is why I bought it, to shoot with open sights.)
I could restock it, but the rifle really shoots so well I am reluctant to mess with it, so now I have to scope it.

My question may be summed up thusly:
What side mount would fit into these three holes?



(Groups shot consecutively, at 50 yards on right and 100 yards on left.)