My 30-40 Krag level load with 150 gr ballistic tips put 5 in 1.5" @50 with 3 in 3/4".
Spent a few hours working up a better scope mounting, Nice thing about having boxes of "stuff".
A typical scope mounting jig doesn't work on the old gal
Found a Leupold front turn in base for a M96 Mauser that fit the front ring. I reworked the rear ring by removing the male dovetail insert and removing the "ears" with dremel and file.. Found a rear Leupold base that fits perfectly.
Getting in on right involves an old trick. Mount the rings on the bases. Pay special attention to centering it rear ring on the rear base (the one with the windage screws) Center with windage and elevation knowbs on the scope. Mount the scope in the rings , snug but able to move in the rings. Take the assembly (suitcase handle) and set it on the rifle. Line up the rear base so it centered left to right. Tighten down the rear scope ring Now clamp the assembly to the rifle with a padded clamp. Install bore sighter. If you picked the right bases you should be close on elevation. To center windage, tap the front ring with a soft hammer to move the base. The ring will move on the scope and the base on the receiver ring but the scope will not as the rear ring secures it. Once you get the windage set, tighten the front scope ring screws. Now complete final windage and elevations in the scope. Should be very minor.
Now, the rings are locked on the bases and the scope is locked in the rings. It should be a rigid assembly.
Now clean base and rifle mating surface with solvent. Put a dab of Gorilla glue on the mating surface, Reinstall and clamp the scope/ring/base assembly. Make sure the rear base is centered up. Look thru the scope at the bore sighter. You may have to tap the front ring/base to center it up.
Now let it dry a couple of days. Remove the scope and using the bases as a guide start youd base screw holes.
Now remove the bases, drill and tap the rifle and mount the bases.
Using an old "long tube" Leupold M8 4X as a trial horse.
More pics as I progress.