Canadian Airgun Forum

What mods are out there to reduce the amount of pumps?Not looking for max fps just less pumps.

I has a 1322 and only pumped it 3 times for indoors playing.
For discouraging feral predators throughout the night, I used 10 pumps.

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Best Wishes
Daryl

Cats?

For the 13xx guns more pumps = more fps with diminishing returns. The older 1377 had a weak piston pump linkage and there is a mod to stiffen it up so the gun pumps more efficiently, maybe you could get away with 8-9 pumps for the same fps as for the stock gun at 10 pumps - don't know never done it. The newer ones use a stiffer component that doesn't require any modding. A flat top piston that is more efficient may also save a pump stroke for the same fps. A longer barrel, same thing. Do all the mods and I expect you could do in 8 pumps what a stock 1377 does in 10 pumps. But if you aren't after more fps, just shoot it as is. Pumpers are made for pumping.

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Iacio ergo sum

Reducing valve volume may also help reaching your goal velocity with less pumps. Just don't over pump or you may experience valve lock, or get a second shot out of the same pumps (air preserving pumper). Important thing to remember is your pistol shall not shoot over 500 with a light pellet, tune accordingly.

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If everything's so lovely yeah, then why don't I, why don't I, why don't I, why don't I feel lovely?

A crosman 362 https://dlairgun.com/collections/crosman-rifles/products/crosman-362-multi-pump-pellet-rifle-c362crs-ar-000which is there newest pumper, achieves the 1377 velocity with less pumps because it has a longer stroke. More air is pumped it the valve with each stroke. It is possible that you have out grown the 1377 and need to move onto a pcp pistol. The volume of air from a single hand pump stoke is fare greater than that of the 1377 stroke. Wes has some in his store https://airgunarcheryfun.ca/air-pistol/

have a great day, Robert

You can adjust the size of the bleed hole in the valve and maybe the transfer port size. I'm not sure how successful this would be because you need to make sure it stays under 500fps at the high pump level. Definitely have a chronograph if experimenting with this pistol. You will get around 550fps with 7.9gr at 10 pumps if you just plug the hole but then you have created an RPAL pistol. With flat tops you will come closer to 600fps so you need a vent and/or constriction system to keep under 500.

Probably the easiest method would be to just plug bleed hole in valve and drill a smaller one or use a tiny sleeve in the hole to get closer to 500fps without going over at the high pump level. This will give you a bit more power at the lower pump levels.

Thanks for all the replies. Off for more research.

The first thing you could try is simply replacing the constricted transfer port with a short section of fish tank bubbler hose. This will enhance the flow through the TP and possibly give you a bit more velocity. But it might not be enough for you. Please let us know how your experimenting goes.

Oh, and if you have an old Phase-2 1377 it could have the brass valve with the large fluted stem rather than the bleed hole approach.

Flat top piston mod...

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Daisy Red Ryder

Do you still make these? I think I got one from you for my 2289 a few years ago.