I recently inherited a 24 power Unertl scope from my father-in-law. I tried using it on a Ruger No. 1 .22-250 with rather dismal results. Won't keep 5 shots on the paper at 100 yards. The rifle shoots MOA with a 9 power Bushnell so I know it's not the gun.

Windage and elevation adjustments are external and seem to be tight but the recoil spring is what's puzzling. How tight should it be, and how much spring compression is recommended? Or is there something else I'm missing?

I haven't been able to find anyone locally who has one and a search for instructions yielded one document that wasn't much help. Any insight would be appreciated.

Cuirrently have one Unertl 24x scope and a Mitchell, which is similar to the Unertl. I had two other Unertl's previously too.
First, make sure the scope is seated correctly in the mounts of the barrel, and/or bridge of the rifle. I don't know if yours it a standard mount Unertl, or a POSA mount one, but you need to have the correct bases for your scope. Then secure the rings to the bases with the large screws on the right side of each ring. No need for over torquing, just snugged up with a coin will do.
Next, at the range, focus objective to the target you'll be aiming at. Loosen the forward lock ring holding the objective glass so you can move the objective in that direction for focusing, or the rear lock ring if you need the objective moved in that direction. Don't believe the markings on the calibrated head as they may not read the distance exactly, just make sure you've taken out all of the parallax. The important thing here is to have the front and rear lock rings untightened so the objective moves freely in either direction, then hand tighten the lock rings when you've eliminated all of the parallax.
In the old days, in the mid 1950's when I had my first Unertl, I would loosen the lock screw holdng the recoil spring so it wouldn't interfere with accuracy. The recoil spring was taken out of the system that way. I manually pulled the scoope tube to its rear battery position after each shot. The lock screw only needs to be tight enough to hold the spring in place, no heavy torque required, if yo0u want to use the spring at all. The 24x Unertl I have now has the lock screw removed. It's no big deal pulling the scope tube rearward after each shot; it becomes second nature.

Don

Thanks, Don, I'll give it a try. But first, I have a new problem. Tried to mount the scope and the large serrated nut on the rear base wouldn't tighten. Gave it a hefty nudge with a wide blade screw driver and the shaft sheared off inside the base with about 1/8" protruding within the hole and part of the shaft stuck inside the nut. I can fix the nut portion but I'm stymied on the shaft. Any idea how the shaft is affixed and how to replace it?