Reduced volume of valve?

[chinaboy]

What does having reduced volume in the valve do?  I'm thinking it increases the overall pressure in the valve.  Therefore, allowing air to pass by quicker and dumping more air in one blast.  Thanks for replies.

[eric]

in a Co2 gun less gas is expelled which leads to less velocity and a higher shot count .in a msp peolpe want as much velocity/fpe(foot pounds of energy) with the least amount of work --- lets say trying to get 300 to 400 fps(maybe even slightly higher) in less pumps .more pumps is counter productive with a reduced volume valve.there are some exceptions though.it does increase pressure but doesn't mean more power/higher fpe as there is less space .   

[quickster47 †]

Eric said it just right.

Carl

[NorthStaR]

Bear with me, how does a smaller valve increase pressure?

It would only increase in pressure if the gas source increased pressure to feed more gas into the smaller volume keeping the pressure up?

Meaning if a Co2 capsule runs at X bar, then the valve will only hold the same X bar unless more gas is compressed along
the way - which doesn't happen - it's more of a transfusion of gas if anything. But if it's a 13XX pumper, then I can see the
logic off the air being compressed more and more on each pump. Does that make sense or am I way off?!   

I just don't get it! I'm having a blonde moment perhaps....pumping I get, Co2 I don't get. It's not logical Captain. 

====================

Actually looking back, I may have just repeated what Eric said in a blonde Europeon way!   

[quickster47 †]

Using CO2 one can only cram so much gas into a given volume.  Reduce the volume of the valve and you can only put in so much gas and the smaller volume of gas actually translates to less force, or a shorter dwell time, behind the pellet heading down the barrel.

I think that is correct but I might have stated it incorrectly or incoherently.

It's that darn white rabbit on my mind.

Carl

[NorthStaR]

It's that darn white rabbit on my mind.
Carl

You-me-both.... love that film! 

And thanks for the info! 

[chinaboy]

I'm still trying to get this.  So, for a pumper...  the reduced volume means less pumps with equal fpe yet less fps than having a regular volume valve.  Am I way off?

[NorthStaR]

My interpretation on it and I've been pondering this a bit - correct me if I'm wrong!!! 

The valve is reduced in volume but the pressure built up inside (from pumping) is the same but with a smaller capacity.
So less pumps to get to the same internal pressure but storing less gas to achieve the same pressure. So 7 will do the same as 10 scenario.

I guess as some air is (normally) wasted on firing a shot, the reduced volume at the same pressure will still have enough ooompf
to propel the pellet home and perhaps more efficiently. More efficient gas use and pumping.

I think that's about right? 

[arkmaker †]

Phil over on the Green has been doing a lot of this same experimentation lately. May want to take a look at some of his threads for ideas.
Rich

[JEBert]

To my way of thinking, a reduced volume valve would be most useful in this scenario.  For instance, if I just shoot targets at 5 or 10M and my 1377 is most accurate with pellet X at 5  pumps.  I don't need or want more FPS.  I add the flat top valve and piston, which should compress more volume of air per pump, and put a small plastic tube in my valve for to reduce the internal space so that I can get more pressure per volume of air in it, and achieve that same fps and accuracy that I used to get with 5 pumps except now I can do the same thing with only 3 pumps.
This is just my take on the reduced volume valve in a 1377 as I haven't done it but this is what I plan to try with one of my guns.  In a CO2 gun it would just reduce the pellet speed and increase shot count.
Cheers

[NorthStaR]

What he said!   

[Daysailer]

To my way of thinking, a reduced volume valve would be most useful in this scenario.  For instance, if I just shoot targets at 5 or 10M and my 1377 is most accurate with pellet X at 5  pumps.  I don't need or want more FPS.  I add the flat top valve and piston, which should compress more volume of air per pump, and put a small plastic tube in my valve for to reduce the internal space so that I can get more pressure per volume of air in it, and achieve that same fps and accuracy that I used to get with 5 pumps except now I can do the same thing with only 3 pumps.
This is just my take on the reduced volume valve in a 1377 as I haven't done it but this is what I plan to try with one of my guns.  In a CO2 gun it would just reduce the pellet speed and increase shot count.
Cheers

What JEBert said   

I went through this same idea to improve plinking and 10-20 yard power for targets with fewer pumps in my 1377.
This link will lead you to my conclusions/results/and thoughts.
http://www.crosman-air-pistol-owners-forum.com/board/index.php?PHPSESSID=1a96ceb76019c795c1bfc257a2339d3b&topic=4088.0

To get the whole picture, you will need to follow EVERY link to link to link, within each link.   
Lots and Lots of good info and great food for thought.

My process started with the SSP's ( Single Stroke Pnuematics) like the X53 Daisy series. 
They have very small air resevoirs but get nice power and accuracy from one pump. 
Lots of Googling, research, thought, and then more of each...
Resulting in my PPPP (poormans perfect plinkin' pistol!

Studying the schematics of the older 1377's, 760's, 1400's, etc, will show that Crosman used a
larger(longer) intake valve in the past.  Unfortunaly no longer available..  But, proves they also knew that
the 1377 type valve is more effecient with less volume.  I think (opinions are cheap) that they
redesigned the best under 10 pump valve volume to cater to the mega-pumper's, 11-infinety, at the
expense of the best overall preformance.   

The volume my experiments showed worked best overall,
was closest to what I percieve was stock in the older designs.

Just my $.02....maybe less.