Some updates on my 2240 build...
I finally completed (well...almost...) my 2240 builds.
First up....after trying various approach to bulk fill my build (tank block and 7oz cylinder; powerlet eliminator and cylinder; 2260 tube with muzzle mack valve bulk fill adapter and disco bulk nipple) I finally decided to go for the simplest approach (atleast for me), 2260 tube with muzzle mack valve bulk fill adapter and disco nipple.
The biggest challenge for me in this build/conversion is to get the velocity down to 500fps. After reading various post on detune and velocity issues, I choose to take this route:
1. replace 2240 valve with smaller diameter valve (c/o Eric...thank you Sir)
2. replace 2240 hammer with lightened hammer (again c/o Eric....most parts are c/o Eric...simply the best)
3. clip spring 1/2 to 1/4 of the coil at a time until the desired velocity is achieved. This is tedious as I have to test for velocity every cut. Infact, I over cut and to compensate, I inserted an Oring as a quick fix.




Below is the result of the velocity test using JSB match diabolo 4.5mm (green can). Testing was done in the basement with ambient temperature. This is a single fill 5 string test.
String 1
1 488
2 488
3 error
4 492
5 496
6 501
7 501
8 error
9 498
10 494
String 2
1 480
2 467
3 478
4 473
5 473
6 479
7 450
8 error
9 486
10 484
String 3
1 481
2 489
3 486
4 error
5 484
6 error
7 488
8 485
9 490
10 error
String 4
1 499
2 error
3 490
4 error
5 483
6 486
7 494
8 error
9 error
10 483
String 5
1 484
2 486
3 error
4 490
5 483
6 487
7 error
8 484
9 error
10 482
In summary, I'm very happy with the outcome of this build. I was able to achieve the velocity, the caliber, and bulk fill set up that is simple and light. This build would have not been possible if not for the valuable contribution of forum members who have shared their knowledge and experience to crosman newbie like me. Thank you very much.
Till my next build....2240 with DC breech and tube