crossman 1377 mods

[jon_89]

Well from what I understand the crosman breech has mounts so I will put my red dot on it. My 2250 started leaking bad and I need to replace the o-rings on the transfer tube, but I am tired of co2. Yep the stock does fit the 1377. Well to sum it all up I am bored just looking for a project.

[jackssmirkingrevenge]

Overpumping will increase the resistance encountered by the hammer ans can actually reduce power, you're better off increasing the stength of the hammer spring and bolt weight.

[Sticky_Tape]

That's what I was thinking Jack. Maybe you could do both pump more and increase hammer strength. Do this use check valves after the pump to chargea chamber? Maybe you could replace the pump with a co2 and ballvalve setup and increase hammer strength maybe it would have the power of a pcp rifle you neva know.

[Gippeto]

Without changing to a metal piston (preferably an adjustable flat top piston), pumping more will be of little benefit. The stock plastic piston simply "mushes" and further pressure in the chamber simply doesn't happen.

Changing the valve spring to a lighter one helps reduce cracking pressure of the check valve (it's inside the valve), getting more air into the chamber with each pump and also reduces the force needed to open the valve.(some what)

A heavier hammer spring is a good idea, but with my 1322 I can dump 40 pumps from a metal flat top piston with the stock hammer spring.

I'll need to do some more port work before I'll be able to judge the effect of a heavier hammer spring.

Modded to the nines, these pump guns will come surprisingly close to the power of a pcp, and at a fraction of the cost.