Caliber
22 Short, Long, Long Rifle.
Check the barrel and receiver
50-300 USD or so
100-1000 USD
Not enough information to answer the question. You fail to describe the finish, overall condition, barrel length, wood, whether the box and papers are present, etc..
solid rib on barrel
Which model in what condition?
Late 1929 according to serial list, the barrel will be marked with date code. Check the Manufactured Date link on the Remington Society of America.
The letters rs represent the car as the "Rally Sport" model.
im almost certain its remmington Stevens Model 520
200-275 USD
1907-1929, 100-375 USD
They are not marked, you can tell by the serial no. (well an looks ;)