1377 is done, chrony test 739 fps, only 10 pumps Video Updated 2/17

[ray1377]

I only pumped it up to 60 one time.
And yes, the pump tube was a tad warm after all those pumps.
With the stock valve spring installed it used to have air left over when I put in 30 pumps.
I could get like 545fps with the first shot and then without pumping it again, load another pellet, cock it
and get a second shot at somewhere around 450fps.
So yes, I've installed a lighter valve spring and it will dump all 60 pumps.
I can't see how a o-ring can be damaged since it does seem to increase in fps when I increase the number of pumps.
If it was leaking, looks like when the pumps went up, that at some point, the fps would bottom out.
Doesn't it?
Thanks
Ray

[airguns100]

I only pumped it up to 60 one time.
And yes, the pump tube was a tad warm after all those pumps.
With the stock valve spring installed it used to have air left over when I put in 30 pumps.
I could get like 545fps with the first shot and then without pumping it again, load another pellet, cock it
and get a second shot at somewhere around 450fps.
So yes, I've installed a lighter valve spring and it will dump all 60 pumps.
I can't see how a o-ring can be damaged since it does seem to increase in fps when I increase the number of pumps.
If it was leaking, looks like when the pumps went up, that at some point, the fps would bottom out.
Doesn't it?
Thanks
Ray

(imo) I'm not a big fan of lighter valve springs, i'd machine the valves (check valve) down to soften things up. plus installing a disco hammer spring (discovery) spring will take care of the rest. here's a example of the machined check valve: http://www.crosman-air-pistol-owners-forum.com/board/index.php?topic=1043.195 page 14 about 6 responses down i took a bunch of pictures in the gallery section of machined brass valves, check valves and stems. AC customs did that.

you might be getting leaks from the transfer port area or the bolt oring. i just had some issues with a bolt i was using, it was allowing air past the bolt oring. i could feel it agaisnt my cheek when i pulled the trigger. another thing thing you can try doing is dusting flour around the breech area (messy) but you'll see where the leaks are coming from, if any.

do you have any photos of your rig? it would help us to remedy your situation Ray

-Rye

edit twice

[ray1377]

Haven't thought about machining the check valve.
But as for leaks, I did the flour test between the breech and pump tube.
And it leaked bad, thats why I did the poly tube mod.
That fixed that.
To tell the truth, I never even thought about the o-ring on the bolt leaking.
Guess I should put some flour around that and see what happens.
Thanks
Ray

[Crosshairs]

Well at least were getting somewere with fixing your gun.
               Mike

[Oane]

I did the flour test between the breech and pump tube.
And it leaked bad, thats why I did the poly tube mod.
That fixed that.

Thanks
Ray

Is the poly tube mod the one where you replace the transport sleeve and seal for a bit of poly tube? I read somewhere the tube can expand and you can lose a few fps by that mod.

[Crosshairs]

I think they need to be cut to perfect size or they will leak,mine is stock.
                   Mike

[airguns100]

Is the poly tube mod the one where you replace the transport sleeve and seal for a bit of poly tube? I read somewhere the tube can expand and you can lose a few fps by that mod.

Quick word of warning.
The poly tube mod is to increase fps. some have had success, some have not. You may just end up having to replace your barrel in the long run.

[quickster47 †]

Early on I gave up on the poly tube modifications.  It just never seemed to work for me and each time I tried it leaked.

Now I use .25" stainless tubing with an I.D. of .211.  This give plenty of flow and when you get it fitted, it never leaks.  It can be difficult to work with and just like the poly tube mod, you need to make sure both ends are perfectly square so you have no leaks.  And also just like doing the poly tube mod, you need to open up your valve port and the barrel port to .25".

Carl

[Crosshairs]

Carl how long do you cut yout tube?
            Mike

[quickster47 †]

Carl how long do you cut yout tube?
            Mike

Mike,

It really depends on the breech and valve I'm using and how deep I've milled the .25" holes.  So what I'm really saying is that each one is pretty much a custom fit piece.  And unfortunately that is just the nature of the beast when you do custom pieces.

Next time I do one or two I will measure them though.

Carl

[airguns100]

Mike.

Here's something you might enjoy reading from last year. http://www.crosman-air-pistol-owners-forum.com/board/index.php?topic=1408.0

[Crosshairs]

OK i think i can do that.Thanks for the info guys.
                    Mike

[Noah]

Just another pic, i kinda like this pic for some reason.
                 Mike

Hey Mike,

WOW - to drool over 

If you don't mind me asking, how much for the whole gig?

[Crosshairs]

I guess about 250.00 bucks for everything
                  Mike