Page 2 of 2 FirstFirst 12
Results 16 to 30 of 41

Thread: Custom Crosman 2240

Hybrid View

Previous Post Previous Post   Next Post Next Post
  1. #1
    Join Date
    Dec 2012
    Location
    Bromsgrove
    Posts
    870
    Quote Originally Posted by tinbum View Post
    I know this is a foolish thought that will lead to money dissapearing faster than in a Polish Lap-Dancing bar, but I want to make a custom pistol and I think the Crosman 2240 is a good base to start from.
    My objective is to make a full power pistol in as small a package as possible. I have done this with TAC, rim-fire and black powder in France, but now want one here where both the "fun" options are out.

    My thought process so far is to shorten the barrel, which I've done before, but also the tube to use 8g co2 caps rather than the usual 12g. After that I would like to reduce the frame in the grip area to reduce height (so I expect custom grips will be needed) and fit a metal breech. I don't want to fit optics, rather make/fit low-profile, fixed open sights.
    I want small and 5 ft/lb, I don't really care about shot count.

    So, I expect there are many who have done this, pics, pointers and tips appreciated.
    Tin ...if you your shortening your barrel but sticking on Co2 5ftlbs aint gonna happen.
    Ive done a few and these figures may prove helpful for a .22 specimen only ..
    Most dramatic velocity increase comes from a longer barrel, mainly required for when the weather gets cold like now and your gun dropping a full ftlb from a stocker barrel.
    You can get 15 to 20 fps by using a fishtank airline gasket of silicone but ive used square section rubber washers to even better effect ....let me know if you want sizes...
    If you machine off the probe section which contains porting and replace with a 2mm stainless steel probe 1.5 mm longer than stock, you will get 15 fos from increased flow and better seating of pellet past the transfer port. Tip of new probe is best with a 2 mm radius.
    Flat topping the valve can create better flow for again 15 fps....
    Chopping your barrel loses roughly 50 fps per 2 inches and increase that for cold condiitions...
    Could keep standard cylinder and lose a bit of barrel to flush it to cylinder length. Above mods then restoring your 50 fps loses ....
    Hammer spring increase will lose you shot count which does not worry you ....but this one gives 12 to 18 fos..
    Use a deltin guide top hat for inside hammer spring with a 3 mm flange for a shade more pre load and removes the twang from the spring and makes it more efficient ...but gains are often smaller than written about on American websites..
    10 to 15 fps at most.
    Last edited by clarky; 22-12-2017 at 09:47 PM.

  2. #2
    tinbum's Avatar
    tinbum is offline Killer Vampire Lesbians on scooters
    Join Date
    Aug 2007
    Location
    Daarn Saaarf!
    Posts
    19,532
    Quote Originally Posted by clarky View Post
    Tin ...if you your shortening your barrel but sticking on Co2 5ftlbs aint gonna happen.
    Ive done a few and these figures may prove helpful for a .22 specimen only ..
    Most dramatic velocity increase comes from a longer barrel, mainly required for when the weather gets cold like now and your gun dropping a full ftlb from a stocker barrel.
    You can get 15 to 20 fps by using a fishtank airline gasket of silicone but ive used square section rubber washers to even better effect ....let me know if you want sizes...
    If you machine off the probe section which contains porting and replace with a 2mm stainless steel probe 1.5 mm longer than stock, you will get 15 fos from increased flow and better seating of pellet past the transfer port. Tip of new probe is best with a 2 mm radius.
    Flat topping the valve can create better flow for again 15 fps....
    Chopping your barrel loses roughly 50 fps per 2 inches and increase that for cold condiitions...
    Useful info! Power at 5 ft/lb should have read "max" on a hot day! Porting, sealing, probing () will offset some of the loss, but I'm just after a short pistol that goes bang and shoots stuff.

    My dinky 120mm derringer produces nearly 40 ft/lb but can't hit bugger all! The 2240 project would be useful if: a) I can legally own it in this country. And b) It has sights that have a noticeable effect on accuracy.
    My ignore list: ​<Hidden information>

  3. #3
    Join Date
    Dec 2016
    Location
    leeds
    Posts
    2,069
    Quote Originally Posted by clarky View Post
    Tin ...if you your shortening your barrel but sticking on Co2 5ftlbs aint gonna happen.
    Ive done a few and these figures may prove helpful for a .22 specimen only ..
    Most dramatic velocity increase comes from a longer barrel, mainly required for when the weather gets cold like now and your gun dropping a full ftlb from a stocker barrel.
    You can get 15 to 20 fps by using a fishtank airline gasket of silicone but ive used square section rubber washers to even better effect ....let me know if you want sizes...
    If you machine off the probe section which contains porting and replace with a 2mm stainless steel probe 1.5 mm longer than stock, you will get 15 fos from increased flow and better seating of pellet past the transfer port. Tip of new probe is best with a 2 mm radius.
    Flat topping the valve can create better flow for again 15 fps....
    Chopping your barrel loses roughly 50 fps per 2 inches and increase that for cold condiitions...
    Could keep standard cylinder and lose a bit of barrel to flush it to cylinder length. Above mods then restoring your 50 fps loses ....
    Hammer spring increase will lose you shot count which does not worry you ....but this one gives 12 to 18 fos..
    Use a deltin guide top hat for inside hammer spring with a 3 mm flange for a shade more pre load and removes the twang from the spring and makes it more efficient ...but gains are often smaller than written about on American websites..
    10 to 15 fps at most.
    sorry mate you talking bollocks on power fairly easy to get a stubby to do 5 in .22
    flat top is for a pumper

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •