Sears/Ranger Model 30 is a Stevens 520(A?)IIRC.

Nice guns. Should be the straight top and bottom profile receiver, not the early stepped profile if I have that correct.
Top tang safety.
That change in profile came in the 1930's I think along with a couple of internal changes.

Lot's of 520's around and under different store brand names. Heavier than the Mod200 in 20gauge but you can still find parts unlike a 200.
12ga 520 by far more common but 20's and 16's are around. Smaller frame than the 12's and nice handling pump guns.
Completely different inside from the 200.
They are a J M Browning design,,unlike the gadgety looking Model 200!