UK Crosman 1377 now restricted to 495 FPS - like Canada

[--ped--]

I wouldn't off centre grind it I'd stone a larger drill bit on a taper if I were to do it but then I wouldn't I'd go through with an 1/8" or if you wanted to be closer an m4 tapping drill
what sort of pressure do you think is in a pumper valve
the op asked how to get it up to like the older American classics and they were a low volume high pressure valve un like the newer easier to pump lower pressure guns
when they brought out the 3 variants with the generic plastic breech they swapped to the larger tp's of 3.6mm as a cost saving cause lets face it they churn thousands and in many US states are classed as cheap toys out and it was easier to standardise them

[luckythirteen]

After selling mine years ago and getting bitten by the Crosman bug again, I ordered one from Poland. It's the new shape but with brown grips and fore end, as well as being full power.

I'm surprised they use any kind of bleed hole or valve mods, it used to just be a reduction in size to the transfer port (sits between the breech and barrel. I bought a couple of brass/Viton ones from and have already fitted one to my 2240. Dead easy to fit, and compatible with Crosman steel breeches.

[Jake190]

After selling mine years ago and getting bitten by the Crosman bug again, I ordered one from Poland. It's the new shape but with brown grips and fore end, as well as being full power.

I'm surprised they use any kind of bleed hole or valve mods, it used to just be a reduction in size to the transfer port (sits between the breech and barrel. I bought a couple of brass/Viton ones from and have already fitted one to my 2240. Dead easy to fit, and compatible with Crosman steel breeches.

Which trader in Poland did you use?
I have a phase one 1377 that I can’t get above 420 FPS on ten pumps, even after changing all the seals(except for the probe seal, which I could not find).
I’m having to put 6 pumps in it, just to cut clean holes in card targets at ten meters

So thinking of selling the phase one and replacing it with a modern 1377 with better velocity. Would prefer a brown gripped model rather than the all black models available in the UK. I think a modern one would only need about 3 pumps for ten metre paper punching.

[--ped--]

the probe seal on the phase 1 and two is a larger bs007

[Jake190]

the probe seal on the phase 1 and two is a larger bs007

Thanks for that Ped. Much appreciated.
Going to order a couple.

[Modski66]

Which trader in Poland did you use?
I have a phase one 1377 that I can’t get above 420 FPS on ten pumps, even after changing all the seals(except for the probe seal, which I could not find).
I’m having to put 6 pumps in it, just to cut clean holes in card targets at ten meters

So thinking of selling the phase one and replacing it with a modern 1377 with better velocity. Would prefer a brown gripped model rather than the all black models available in the UK. I think a modern one would only need about 3 pumps for ten metre paper punching.

When you say 'phase one' is the type with the sliding breech cover and cocking knob at the back end of the body?

If so, the one I used to have had a bleed/vent hole on the underside of the valve body, it was hopeless until I plugged it. Didn't have a chrono' back then, so don't know what change it made to fps, other than it was significant.

[harvey_s]

When you say 'phase one' is the type with the sliding breech cover and cocking knob at the back end of the body?

If so, the one I used to have had a bleed/vent hole on the underside of the valve body, it was hopeless until I plugged it. Didn't have a chrono' back then, so don't know what change it made to fps, other than it was significant.

Interesting, when you said yours was an early model, I assumed you meant an early model brass bolt model.
I didn't realise the sliding breech/rear cockers were also affected...

[Jake190]

When you say 'phase one' is the type with the sliding breech cover and cocking knob at the back end of the body?

If so, the one I used to have had a bleed/vent hole on the underside of the valve body, it was hopeless until I plugged it. Didn't have a chrono' back then, so don't know what change it made to fps, other than it was significant.

Yes, it’s a March 1980 model with the sliding breech, rear cocking knob and one piece grip.
I have changed all the seals (except probe) and the FPS has got marginally worse. The breech screw does not seem to clamp the barrel down to the receiver securely enough to eliminate leakage at the transfer port.

Thanks for the tip in respect of the valve body. Mine is brass and has the hole underneath. What did you use to plug the hole?
I think I will give your suggestion a try. It would be great to get this pistol to the stage where I could do some indoor paper punching on three or four pumps instead of the six pumps it currently requires.

[--ped--]

check the state of the breech where the screw is as they crack there
i have them in stock but postage is more than they would cost

[Modski66]

I used a small brass screw from my random collection, wound it in until it was tight (making sure the point did not poke into the valve) then cut off the excess and filed it smooth.

[Jake190]

check the state of the breech where the screw is as they crack there
i have them in stock but postage is more than they would cost

Thanks Ped, I will check the breech.

[Jake190]

I used a small brass screw from my random collection, wound it in until it was tight (making sure the point did not poke into the valve) then cut off the excess and filed it smooth.

Thanks for the advice Modski66.

[luckythirteen]

Which trader in Poland did you use?

I'll send you a PM with the place. They seem to be quite common in the rest of Europe but I can't recall seeing one in the UK lately

[Jake190]

I'll send you a PM with the place. They seem to be quite common in the rest of Europe but I can't recall seeing one in the UK lately

Thanks for that.

[Zeroexpo1]

I'll send you a PM with the place. They seem to be quite common in the rest of Europe but I can't recall seeing one in the UK lately

I'd also like a full power brown version if you'd be so kind as to provide details of the Polish retailer?