Crosman pump pistol

[JPSAXNC]

What was the Crosman pump pistol that used the blowoff valve, instead of the knock open valve. TIA

[Blowpipe Sam]

The models 130 and 137 were self cockers from the fifties.  I don’t know if Crosman made another pump pistol between the 130’s and the 13XX.

[Nee Zee]

What is a blowoff valve?

[avator]

Some refer to it as a knock open valve as opposed to the hammer hitting the poppet type.
They reset the valve on the first pump.

[Blowpipe Sam]

The sear holds a cap closed on the valve.  Pulling the trigger releases the sear and allows the cap to blow open and release the pressure.  Because of the way the trigger engages the sear the trigger pull gets heavier with every pump you add. A spring pushes the cap closed when the pressure drops and the sear locks when the trigger resets.  The cap will set back slightly against the sear with the pressure of the first pump completing the cocking cycle.

Poppet valves don’t adversely affect the trigger pull so Crosman replaced the self cockers with poppet valve designs as soon as they acquired the patents from Benjamin.

[Nee Zee]

Learning new stuff here. 

So it sounds like a "blowoff valve" type gun doesn't need a hammer, is that correct?

[Mzq284]

The 1300 Medalist was another. I believe they came after the 130, sort of an updated version.  They had some of crosmans red swirl plastic grips and forend. I had one, they're about 2 inches shorter than the 13xx guns. They have a good feel and balance, but the trigger gets harder with each pump, mine was horrendous. I just bought a 130 for a project, they're pretty cool. If I found a mint one I would reseal it and enjoy it as is.

[Blowpipe Sam]

The blow open guns don’t need a hammer but the sear and its spring look a lot like the present hammer and spring arrangement.  When Crosman updated the guns it was pretty easy to substitute the hammer and poppet valve in the same space. Thus the 760 evolved from a blow open valve to a knock open valve.

[JPSAXNC]

Thanks for the replies!