Crosman Air Pistol Owners Forum

Crosman air pistol - General => Crosman air pistol - General discussion => Topic started by: mcc1961 on March 09, 2012, 08:16:20 PM

Title: Flat top piston and valve???
Post by: mcc1961 on March 09, 2012, 08:16:20 PM
I have a FT piston and valve coming today that I got from Mr. Mellon and was wanting to know what is the max pumps I can do with it?
Title: Re: Flat top piston and valve???
Post by: 1377x on March 09, 2012, 08:20:38 PM
with a stock hammer spring 14 then the valve will retain air
Title: Re: Flat top piston and valve???
Post by: 1377x on March 09, 2012, 08:26:00 PM
oops forgot to add
if you get mellons power adjuster i have never tried one up to 20 pumps ???
if you go with a disco hammer spring iirc 25 pumps any more than that doesnt get the numbers any higher.
someone might say it is harder to cock the gun imo its about the same
if you already cocked a disco then you know already ;)
Title: Re: Flat top piston and valve???
Post by: woody67 on March 09, 2012, 09:40:43 PM
Melon's valve is a monster. It will hold over 40 pumps and fire (with the right setup of springs) without a problem.
1377X is right though, with stock spring set up the valve will retain air after @14 pumps.



If you're the one who's trying to put it in your 2240, You can pump it up as many times as you want. Haha ;)
Title: Re: Flat top piston and valve???
Post by: 1377x on March 10, 2012, 12:23:38 AM
i have a .041 stainless steel spring wire that can dump 60 pumps
the gain between 35-60 pumps is not worth it
at 35 pumps i can launch a 21g kodiak at 662fps thats 20fpe out of a 2289g :D :D :)
pumping past 35x might get me 12fps more :(
not to mention you need a cheater bar to cock it :o ;D ;D ;D
the disco spring gets me to 12fpe in 15 pumps.i dont need any more than that
i see the UK guys taking small game at 40yds sub 12fpe.if they can do it so can i. the gun is accurate enough, it is then left up to the shooter
Title: Re: Flat top piston and valve???
Post by: AZAG on March 10, 2012, 02:14:09 AM
Will heavier pellets cause the valve to retain air at a lower number of pumps?  I have a FT piston and valve in my 22 cal carbine and it retains air at 10 pumps with 14.5 gn pellets.
Title: Re: Flat top piston and valve???
Post by: 1377x on March 10, 2012, 02:17:37 AM
Quote from: AZAG on March 10, 2012, 02:14:09 AM
Will heavier pellets cause the valve to retain air at a lower number of pumps?  I have a FT piston and valve in my 22 cal carbine and it retains air at 10 pumps with 14.5 gn pellets.
the first thing that comes to mind is your hammer spring is weak
where did the valve come from
Title: Re: Flat top piston and valve???
Post by: AZAG on March 10, 2012, 02:54:18 AM
Its a Mellon Air Piston and Valve.
Title: Re: Flat top piston and valve???
Post by: 1377x on March 10, 2012, 02:58:28 AM
Quote from: AZAG on March 10, 2012, 02:54:18 AM
Its a Mellon Air Piston and Valve.
my first guess would be weak hammer spring
maybe sear drag
how old is the gun?
Title: Re: Flat top piston and valve???
Post by: AZAG on March 10, 2012, 03:06:06 AM
Quote from: 1377x on March 10, 2012, 02:58:28 AM
my first guess would be weak hammer spring
maybe sear drag
how old is the gun?

I don't think that any of the individual pieces are very old.  All less that a year.  It started life as a reman 1377, and converted to 22cal carbine.  It has a power adjuster that I haven't played with, it may be in the "all the way out" position.
Title: Re: Flat top piston and valve???
Post by: 1377x on March 10, 2012, 03:11:36 AM
Quote from: AZAG on March 10, 2012, 03:06:06 AM
I don't think that any of the individual pieces are very old.  All less that a year.  It started life as a reman 1377, and converted to 22cal carbine.  It has a power adjuster that I haven't played with, it may be in the "all the way out" position.
i sent you a pm after seeing the gun in the gallery if its the one you are talking about
when i saw the adapter that was the next solution did you adjust the power adjuster?
try that and report back
Title: Re: Flat top piston and valve???
Post by: mcc1961 on March 10, 2012, 04:43:47 AM
I put the gun together today .I have a Disco hammer spring with power adjuster,Cothran trigger,TKO trigger kit,24" barrel, FT valve and piston  and muzzle brake.I also painted it with truck bed liner on the stock and pumparm.Here is the finished product.
Title: Re: Flat top piston and valve???
Post by: 1377x on March 10, 2012, 04:50:02 AM
wow!
thats one fine shooter you have there!!!
a disco hammer spring and power adjuster.how times are you planning on pumping :o
pellet holer in a good place
that rig is going to be one hard hitting shooter
i would like to see how a 18gr jsb pellet would register out it :).heck even a 21gr pellet if you want to pump it 25x
it going to be quiet for sure
nice job!
Title: Re: Flat top piston and valve???
Post by: mcc1961 on March 10, 2012, 04:59:41 AM
It's only a .177 but what FPS do you think i get with 7.9 grain pellets.Just a guesstimate ,don't have a chrono.
Title: Re: Flat top piston and valve???
Post by: 1377x on March 10, 2012, 05:07:57 AM
Quote from: mcc1961 on March 10, 2012, 04:59:41 AM
It's only a .177 but what FPS do you think i get with 7.9 grain pellets.Just a guesstimate ,don't have a chrono.
i would say 700+ depending on how many pumps 10 or more.with your spring set up you could easily go to 25
if you do that many pump slow so the gun doesnt heat up
heck you coud go with a 10.5gr pellet with the parts you have
Title: Re: Flat top piston and valve???
Post by: quickster47 † on March 10, 2012, 01:42:13 PM
If you are shooting paper use the lighter pellets. If you are going for stopping power for vermin use the heavier pellets.

Carl
Title: Re: Flat top piston and valve???
Post by: AZAG on March 11, 2012, 04:17:53 AM
Quote from: 1377x on March 10, 2012, 03:11:36 AM
i sent you a pm after seeing the gun in the gallery if its the one you are talking about
when i saw the adapter that was the next solution did you adjust the power adjuster?
try that and report back

I gave the power adjuster a couple of turns and now it dumps 15 pumps.
Title: Re: Flat top piston and valve???
Post by: 1377x on March 11, 2012, 04:25:51 AM
(http://serve.mysmiley.net/sign/sign0173.gif)
glad you got it figured out
Title: Re: Flat top piston and valve???
Post by: mcc1961 on March 11, 2012, 07:55:19 AM
How can you tell if one is holding air after the shot?
Title: Re: Flat top piston and valve???
Post by: ceejay on March 11, 2012, 01:55:32 PM
Quote from: mcc1961 on March 11, 2012, 07:55:19 AM
How can you tell if one is holding air after the shot?

1 - re-cock

a) discharge at a freely hung paper towel or tissue -or-
b) hold hand in front of barrel and pull trigger - - - - NOT recommended !!

Title: Re: Flat top piston and valve???
Post by: 1377x on March 11, 2012, 01:59:26 PM
Quote from: ceejay on March 11, 2012, 01:55:32 PM
1 - re-cock

a) discharge at a freely hung paper towel or tissue -or-
b) hold hand in front of barrel and pull trigger - - - - NOT recommended !!
do as ceejay says and do not pump after first shot