Crosman 1377 advice

[--ped--]

yes it will increase volume
rather than fit a spacer fit a longer spring from either a current 1377 or use a crosman sear spring(only use for them as they're crap as a sear spring)
what you'll find is that you have to pump a bit more but it will be easier to do
I prefer using the high volume low pressure approach other how yours is now with a low volume and high pressure

[Modski66]

You sound like a pneumatics engineer....

[--ped--]

no just worked on a lot of crosman pumpers from vintage to modern

[Modski66]

The 1377 is back together for a functional test, and it certainly functions now! It has quite a bit of poke...
Not sure about the barrel condition though, shots are not grouping well, but that might be that the front sight is very skinny and difficult to keep central in the rear notch.
I am going to trial modify the front blade to test out my theory. Not keen on trying to replace this phase one barrel...

[--ped--]

lighten the sear spring it usually helps accuracy I don't do a kit for phase 1 frames but do for phase 2 onward and 22xx frames

[Modski66]

I have squashed the spring in a vice and fitted a modified 22lr case as a guide. Can I trim a couple of coils off without ruining it?

[--ped--]

if it has a phase 1 frame it already has a guide and the sear springs on these are much lighter than the later phase 2 and current frame