Optimizing a Crosman 2240 with 7.5"barrel

[Blue]

If I remember correctly when you remove the front sight its a slip on fitting that is centered by way of a flat spot on the end of the barrel and a corresponding flat inside the sight.  I think theres a ledge inside the sight which the barrel butts up to keeping the sight from going any further down the barrel.

I carefully drilled out the front sight to eliminate the flat and the ledge which allowed it to slide back exposing the end of the barrel.  The LDC is a 5" TKO which presses on the end of the barrel and is secured by a couple set screws so I needed to have a small amount of barrel exposed to get it on.

Leaving the front sight is more for looks since I use the red dot.  If I was planning on having the sight functional I'd try to fix it in place with an adhesive or set screws.  It doesn't really move but I'd want a little insurance against it rotating without me noticing if I were to rely on it.

Blue

[rsterne]

If you use a Pro-Top (are they even made still?) you can use the back end of a Disco valve, the Pro-Top replaces the front end.... If you then use a Disco poppet, it will open slightly easier (but that is not an issue at CO2 pressures anyways).... Being harder, it may not seal as well if there is any dirt or nicks on the seat.... You can also just fit a Disco poppet into the 22XX valve, instead of buying the whole valve and throwing away the front end....

I think the reference to "lift shrouding" would mean that the Disco poppet, being harder and flatter, will have a slightly smoother path for the CO2 across the seat of the valve, requiring slightly less lift to get the same flow.... This is not really an issue, as you can always add a fraction more preload on the hammer spring to get that lift with a stock poppet....

I don't really see any advantage to using a Disco valve on CO2....

Bob

[Dutchie]

If I remember correctly when you remove the front sight its a slip on fitting that is centered by way of a flat spot on the end of the barrel and a corresponding flat inside the sight.  I think theres a ledge inside the sight which the barrel butts up to keeping the sight from going any further down the barrel.

I carefully drilled out the front sight to eliminate the flat and the ledge which allowed it to slide back exposing the end of the barrel.  The LDC is a 5" TKO which presses on the end of the barrel and is secured by a couple set screws so I needed to have a small amount of barrel exposed to get it on.

Leaving the front sight is more for looks since I use the red dot.  If I was planning on having the sight functional I'd try to fix it in place with an adhesive or set screws.  It doesn't really move but I'd want a little insurance against it rotating without me noticing if I were to rely on it.

Blue

Yes, that's how the stock front sight works. I think I will try to glue or screw a fibre optic front sight on top of a silencer adapter, and use a threaded moderator. What's your impression of the 5" TKO's performance? I do like its small size.

Another thing I'm thinking about is to make a front sight that consists of a tube, giving me a circle as a front sight enabling me to see through it.

If you use a Pro-Top (are they even made still?) you can use the back end of a Disco valve, the Pro-Top replaces the front end.... If you then use a Disco poppet, it will open slightly easier (but that is not an issue at CO2 pressures anyways).... Being harder, it may not seal as well if there is any dirt or nicks on the seat.... You can also just fit a Disco poppet into the 22XX valve, instead of buying the whole valve and throwing away the front end....

I think the reference to "lift shrouding" would mean that the Disco poppet, being harder and flatter, will have a slightly smoother path for the CO2 across the seat of the valve, requiring slightly less lift to get the same flow.... This is not really an issue, as you can always add a fraction more preload on the hammer spring to get that lift with a stock poppet....

I don't really see any advantage to using a Disco valve on CO2....

Bob

Wouldn't a Disco poppet, giving a smoother path for the CO2, achieve the same thing as widening the transfer port and angleing the valve "outlet" (forgive me if I'm using the wrong terms)? That is, hopefully, getting more gas behind the pellet faster before it leaves the barrel? I think what I want to try is to make the flow of the CO2 as smooth as possible, and then adjust the force of the hammer hitting (in the various ways described here) so that it doesn't waste any CO2.

Do you think the idea of getting the gas out of the valve and into the barrel as fast as possible is conceptually sound for increasing FPS, however slight? What I mean by this is that hopefully I can use a lower volume of CO2 per shot to increase efficiency, but getting that lower volume into the barrel faster to offset any losses in velocity by using less CO2, or potentially even gaining a (very) small increase in average FPS (not total cumulative FPS) while also gaining efficiency.

Edit: I put one piece of your reply in bold text, that's the reason why I'm asking this.

[Blue]

I like the 5" TKO, although I've never tried any other size.  I too didn't want anything longer than it needed to be.

I've heard that the longer ones are better for higher power rifles but the 5" allows me to shoot quietly in the basement without disturbing anyone above.

I'm pretty sure TKO (www.TKO22.com) makes threaded versions in fact I think he makes one for the Maximus (I think only the Euro Hunter model is the version that comes with a threaded adaptor).  You could see if you can order one from Crosman, I don't know if the Maximus barrel and the 2240 barrel are the same OD.  Prices are cheap, flat $4 shipping, you just have to find the correct part number by going through their EVP's on the website.  You could also call him to see if he has any recommendations for an adaptor that will interface with your barrel and his LDC.

I've heard good things about Rocker1's custom shrouds and LDC's.  He's one of the moderators here, you could look him up and send him a message inquiring what he might be able to offer.

Blue

[rsterne]

Not really.... the flow around the poppet is two 90* turns within a very short distance, and the flow area is dependant on the lift.... In the case of the softer, stock poppet, is gets a bit of a "groove" in it (because it's soft), so it has to open a bit further to get the same area for flow.... There might be a theoretical advantage to using a Disco poppet, but I defy you to be able to measure it.... and it is more prone to leaking on CO2 because of the lower pressure and the dirt sometimes found in CO2 cartridges....

Smoothing the flow BEHIND the valve throat, by angling the port and rounding the bottom end is altering something that is of fixed dimensions, you don't have the option of just opening the valve a few thou further like you do with the poppet.... Better flow there will deliver the CO2 that the valve releases to the pellet in a more efficient manner....

Bob

[fivestar45]

If you use a Pro-Top (are they even made still?) you can use the back end of a Disco valve, the Pro-Top replaces the front end.... If you then use a Disco poppet, it will open slightly easier (but that is not an issue at CO2 pressures anyways).... Being harder, it may not seal as well if there is any dirt or nicks on the seat.... You can also just fit a Disco poppet into the 22XX valve, instead of buying the whole valve and throwing away the front end....

I think the reference to "lift shrouding" would mean that the Disco poppet, being harder and flatter, will have a slightly smoother path for the CO2 across the seat of the valve, requiring slightly less lift to get the same flow.... This is not really an issue, as you can always add a fraction more preload on the hammer spring to get that lift with a stock poppet....

I don't really see any advantage to using a Disco valve on CO2....

Bob

Yes the Pro-Top's are still around. And the Disco valve seat and stem combination do seal and work well at co2 pressures. I have found that Disco stems do not seal reliably in a 22xx valve body as the 22xx seats that I've seen usually have nicks and marks in them that usually only seal with a softer more compliant stem.


For the folks that haven't seen a Pro-Top here are a few pic's.
From the left Pro-Top on a Boss valve Disco valve ,22xx, and an OEM 22xx


Here's what is in them


Looking into the captured powerlet seal and piercing pin


Here are some before and after chrony strings I did on a brand new bubbly pack 2240. All that was done was to cut the piercing pin off the OEM stem with a Dremel. These were done in about 68deg f basement no time taken between shots just loaded and shot. As can be seen the test pellets were Hobbies which will be a bit faster in both tests.

[Dutchie]

I like the 5" TKO, although I've never tried any other size.  I too didn't want anything longer than it needed to be.

I've heard that the longer ones are better for higher power rifles but the 5" allows me to shoot quietly in the basement without disturbing anyone above.

I'm pretty sure TKO makes threaded versions in fact I think he makes one for the Maximus (I think only the Euro Hunter model is the version that comes with a threaded adaptor).  You could see if you can order one from Crosman, I don't know if the Maximus barrel and the 2240 barrel are the same OD.  Prices are cheap, flat $4 shipping, you just have to find the correct part number by going through their EVP's on the website.  You could also call him to see if he has any recommendations for an adaptor that will interface with your barrel and his LDC.

I've heard good things about Rocker1's custom shrouds and LDC's.  He's one of the moderators here, you could look him up and send him a message inquiring what he might be able to offer.

Blue

I did some searching on google, and I think that the adapter that I posted in my original post, is actually a Maximum adapter being sold as a 2240 adapter by the Dutch webshop where I found it. So that might work, but I'll do a little more research before I buy. Thanks for the leads.

I'm gonna have to decide between a smaller silencer like a TKO for looks (if you say doesn't bother people one floor up it's fine in terms of noise), or a bigger one like the Weihrauch which I think I remember reading that the hammer is louder than the CO2 pop with that, which is pretty cool and impressive too. Especially with some efficiency mods (especially the hammer bounce) it could get really quiet that way.

Yes the Pro-Top's are still around. And the Disco valve seat and stem combination do seal and work well at co2 pressures. I have found that Disco stems do not seal reliably in a 22xx valve body as the 22xx seats that I've seen usually have nicks and marks in them that usually only seal with a softer more compliant stem.


For the folks that haven't seen a Pro-Top here are a few pic's.
From the left Pro-Top on a Boss valve Disco valve ,22xx, and an OEM 22xx


Here's what is in them


Looking into the captured powerlet seal and piercing pin


Here are some before and after chrony strings I did on a brand new bubbly pack 2240. All that was done was to cut the piercing pin off the OEM stem with a Dremel. These were done in about 68deg f basement no time taken between shots just loaded and shot. As can be seen the test pellets were Hobbies which will be a bit faster in both tests.

(Had to remove your images in order to post)

In that shot string, is the increase in power to be attributed to the piercing pin taking up volume in the valve, and so increasing volume by cutting it off? I suppose you did get fewer useable shots with the piercing pin removed?

Also, what's a Boss valve? Another valve from a different gun? It looks the same to me from the outside as a 22xx valve.

[kj]

op...seems you have a bit of confusion. the p-rod is a separate pcp pistol made by crosman. so when talking about a p=rod hammer or trigger group , they come from this pistol. again i'll suggest you look at the diagrams on the crosman site to help gain a better understanding of how things work and what things are when people talk about them. also you'll need the part numbers if you order from crosman. many of crosman parts are interchangable. this modular approach makes it easier for crosman and more fun for modders.

the p-rod hammer is drilled through to allow an allen wrench to slide through from the back to make the throw adjustment. there is a place on the treaded part of the striker to accept the allen wrench.

i believe anodizing is only for aluminum. you can look i nto it further.

boss valves ar after market valves that come in the 12gram cartridge stayle and bulk fill style. they're already modded

peace
kj

[Dutchie]

op...seems you have a bit of confusion. the p-rod is a separate pcp pistol made by crosman. so when talking about a p=rod hammer or trigger group , they come from this pistol. again i'll suggest you look at the diagrams on the crosman site to help gain a better understanding of how things work and what things are when people talk about them. also you'll need the part numbers if you order from crosman. many of crosman parts are interchangable. this modular approach makes it easier for crosman and more fun for modders.

the p-rod hammer is drilled through to allow an allen wrench to slide through from the back to make the throw adjustment. there is a place on the treaded part of the striker to accept the allen wrench.

i believe anodizing is only for aluminum. you can look i nto it further.

boss valves ar after market valves that come in the 12gram cartridge stayle and bulk fill style. they're already modded

peace
kj

Oh! I was wondering why there were so many different p-rod parts, I thought it was like a whole upgrade kit sold by some little webshop. 

I have looked at the exploded view of the 2240 and 2300T. I understand how everything works, but I didn't look very closely at what everything is called. Will do that some more. Also, for anybody reading along now or in the future, this pictures was also quite useful alongside the exploded view to figure out how the gun works:


I looked into the Boss valves, I would probably be better off modding the stock valve if needed.

Edit: Looked it up and a p-rod is a Benjamin Marauder apperantly.