The Unertl scope was made by the firm of John Unertl. Unertl was one of the premier scope makers in the target shooting community in the '30s. The USMC liked them enough to adapt the 8X to their sniper version of the Springfield 1903 rifle. Remember the scope on the GI's sniper rifle in Saving Private Ryan? Not the short receiver mounted Lyman Alaskan (M81 or M82) used earlier in the movie but the long barrel mounted one which was featured when there was a sniper v. sniper duel? That's a Unertl and the Unertl saw extensive service with the USMC in WWII, Korea, and Vietnam (Hathcock's Model 70 was equipped with a Unertl).
I'm no expert on Unertl scopes but most of them, except for the current one used today by the USMC, have no internal adjustment capability and were adjusted by their mounts. I'm not sure what the "20" is and if it a high magnification, perhaps it means 20 power (someone please correct me if I'm wrong).
The firm is still around and supplies the 10x scope the USMC uses on their M40A1 Sniper rifles. I think the son (or was it grandson just passed away recently).
I'm not sure on this but I believe that the original Unertl was a sniper in WWI. It is reputed that he (or was it somebody else) layed out in no-man's land for three days, defecating in his pants so as not to move, to wait for his target. He got it and returned to American lines.
Your Remington Model 37 Target Rifle was first issued in 1937. For more information, I suggest you repost in Harley Nolden's forum here at the Firing Line. Harley's library makes mine look like the children's section.
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