My 1322 not discharging all the air..

[winchester0080]

I have modified valve and piston and have only been pumping 10 pumps. I got a wild hair to see if 15 pumps or more would increase anything and it does. I pumped the gun 20 times and it didn't discharge all the air i had to cock it 3 times to get all the air out. 15 pumps it discharges all the air but more than that it doesn't. What could be causing this ?

[Gertrude]

Lets see if I get this right,
at 20 pumps your valve is retaining air.
 you can get a stronger hammer spring and it will cure the problem, but will also cause the trigger to have a heavier pull.

[Onebaddj]

x2 what he said.

when you pump more air pressure into the valve that is more pressure holding the valve shut.

[BillK]

Sounds like you need a hammer spring guide.  About $5 at Mountain Air.  If that doesn't do it you can shim the guide with a washer or two.

[David Powell]

I had a Crosman 120 pump up rifle that had a weak hammer spring and I got two shots from ten pumps. Came in handy plinking lol! Like others said have stated, hammer spring.

[winchester0080]

Ty for information . I have purchased 3 different springs same diameter 1 same 1 longer and really long in case other 2 didn't work. The stiffer 1 little longer wouldn't cock . I shorten the spring by the time it cocked it was so short it wouldn't put enough pressure on the hammer. So I put same size stiffer same thing wouldn't cock. So I suppose have to find same gauge little longer stiff not working for me lol.

[breakfastchef]

Pretty tough to dump 20 pumps in a 13xx gun. Heavier hammer spring may not be the best way forward. Try a lighter valve spring. A stock Crosman sear spring with a few coils clipped off has worked for me. You will have to cock the gun before pumping with the lighter valve spring installed.

What sort of valve mods did you do? Perhaps there is something we have not learned about your setup that would be of interest.

[rsterne]

The hammer spring from a Disco will work, and with a "set" (ie compressed then released) sear spring inside the valve will let you pump until you're tired of pumping and you're not really gaining any more velocity....

Bob

[winchester0080]

Breakfastchef I made port hole bigger on valve cut 2 threads off male end of valve angle drilled in port so its not 90 deg now its more easy for air to get out and cut and grinded valve head flat. Filed pin so not so sqaure it said that would make it easier for the air to flow. Installed adjustable flat head piston..