2240 mods

[Paul]

I got one of the new Crosman 2240's with the plastic sides
I fitted a steel breech. a large transfer port, a 14'' barrel plus the noise extension and a new polished sear.
using CO2 I get 562 feet per second for about 24/26 shots, I was happy with that.
Then I removed the Air chamber, did the cut thread mods and remove the old threads in the body to make more room for air, then altered the angle of the air outlet to transfer port, finally I removed the edges of the valve stem to allow air to flow easier and reduced the pin thickness to allow air to pass easier around it, so that should be about 60 FPS more I was guessing.... instead I now get 60 FPS less..... any thoughts Guys and Gals??? I have ordered an other stock Valve, today from Gmac.

[quickster47 †]

Sounds like your original build was right at being extremely efficient if you were getting 562 FPS.  Now it sounds like with all your gas improvement mods you are wasting gas and might be better off with a longer barrel to make use of that extra gas.

Is everything nice and tight and you have no gas leaks?

Did your shot count decrease significantly with your latest mods?

And I'm not sure if it's any one particular mod causing the problem but perhaps the combination of all the mods.

Carl

[CraigH]

That is a strong 2240.  I would first check the transfer port with tissue paper.  Then internal seals.

[Paul]

That is a strong 2240.  I would first check the transfer port with tissue paper.  Then internal seals.

Hi Craig
Sorry I'm not sure how to check the transfer port with Tissue paper, please excuse my ignorance and explain or point me to a post if you know of one thanks.

[Paul]

Sounds like your original build was right at being extremely efficient if you were getting 562 FPS.  Now it sounds like with all your gas improvement mods you are wasting gas and might be better off with a longer barrel to make use of that extra gas.

Is everything nice and tight and you have no gas leaks?

Did your shot count decrease significantly with your latest mods?

And I'm not sure if it's any one particular mod causing the problem but perhaps the combination of all the mods.

Carl

Hi Carl
Thanks for the reply, I suppose a process of elimination will follow one the new Valve and housing arrives.
I will check the shoot count tomorrow, I was so disappointed with the chrono readings I sort of put it to one side to try and figure out in my mind what had happened.

[quickster47 †]

That is a strong 2240.  I would first check the transfer port with tissue paper.  Then internal seals.

Hi Craig
Sorry I'm not sure how to check the transfer port with Tissue paper, please excuse my ignorance and explain or point me to a post if you know of one thanks.

Take small pieces of Kleenix or tissue paper and lay it by the breech where the transfer port is.  When you fire the gun these pieces of tissue should not be blown away.  If they do then you probably have leaks around the transfer port.

Carl

[quickster47 †]

Hi Carl
Thanks for the reply, I suppose a process of elimination will follow one the new Valve and housing arrives.
I will check the shoot count tomorrow, I was so disappointed with the chrono readings I sort of put it to one side to try and figure out in my mind what had happened.

I totally understand being frustrated with your build and I also know that backtracking and doing a process of elimination is a real PITA but often that is the only thing to do.

I had a build like yours at one time and believe it or not it had an almost identical problem.  And just like you, I put mine aside only I never went back to visit mine again.  I think I tore the gun down and used the pieces parts in other projects.   So don't give up on yours as I would like to know what you find.  Go ahead and do the process of elimination to solve the problem.

Carl

[CraigH]

I only yesterday suffered disappointment and generally do not do so gracefully.  And I am now steeling myself for potential either way on my next effort.     Keep the faith and try again and slowly proceed.

[ped]

if you wet the tissue it sticks to the breech and tube-I use small pieces on both sides and also put a piece over the loading port

[quickster47 †]

if you wet the tissue it sticks to the breech and tube-I use small pieces on both sides and also put a piece over the loading port

Sort of forgot about making the tissue damp so that it remains in place better.  Good catch ped. 

Carl

[1377x]

When you altered the valve stem which edges do you mean? When reducing the pin thickness did you reduce the thickness of the whole pin? Reducing it where it sticks out and the hammer hits may cause a leak

[quickster47 †]

Hoping he did it something like this but not this radical.  I don't even do mine like this any more.  More of a concave finish now days.

Carl

[1377x]

Hoping he did it something like this but not this radical.  I don't even do mine like this any more.  More of a concave finish now days.

Carl

holy tomoly!!!
Would that bend when struck by the hammer?

[quickster47 †]

holy tomoly!!!
Would that bend when struck by the hammer?

No problems so far and I've probably got roughly 1,500 rounds on one of them.  Fortunately the force is all on the end and there's no lateral (side)  force.  It even punctures Powerlets so it is okay.

However, I could tell no significant gains doing them like that so now days I do them more like what is shown in this picture.  Lots easier to do.  Only thing is you need to be careful as to not let the shaft get to hot or you will ruin your stem seal.  Don't ask me how I know this, twice. 

Carl

[Paul]

Thanks all you guys, I have now got the new parts from England.
So I just need some time from making Racing drones to get back to Gunsmithing.
Will try the tissue trick thanks for the heads up on that.
I will post my results when I have some