100 and 101 Pump Rifles

The Crosman 100 is .177 caliber and the model 101 is .22 cailber.  The guns are the same except the barrels and bolts have to be for the same caliber.  There are at least 2 different versions of these models.  The most obvious difference is the shape of the receiver.   Pre-War guns are flat on top and Post-War guns are rounded.  There are other differences especially in the valve parts and sights which are not interchangeable.   You will need factory tools to disassemble and re-assemble the valve.  We recommend disassembling your gun and inspecting the internal parts so you can order the correct replacement parts.