Supported by an impressively wide and diverse, domestic and foreign aftermarket of custom parts and accessories availability, probably no other airgun platform is as widely customized as Crosman's contemporary Co2 pistol-model line-up. Here is yet another example; this one a good example of the personality and performance benefits of converting from Co2 to air power. These things are almost more FUN than should be legal!
.22 Crosman 2240 Custom Carbine bolt-action Co2 single-shot
14.3gr JSB Express, 82F, 5 shot string (approx. 20 shots/charge at full power)- Low= 587, Hi= 607, ES= 20, SD=5, Avg= 598 FPS/11.4 FP
The Same .22 Crosman 2240 Custom Carbine converted to regulated high-pressure-air
14.3gr JSB Express, 3500 PSI fill, 40 shot powerband- Low= 696, Hi= 713, ES= 17, SD= 3, Avg= 701 FPS/15.5 FP
Smitten with the lovely 2240 Custom C02 Carbine above, but ever-wondering “what if”, it took quite a leap of faith to roll the dice on a regulated HPA conversion kit on Ebay (from Taiwan) consisting of a replacement main tube, brass hammer, regulated drop-block, and 6,000 PSI rated “titanium” chamber-tube. But after several hours of fitting, sanding, fiddling and cussing, the results are gratifyingly impressive. Whether running on Co2 or air, the little carbine consistently averages 3/4” to 1” groups at 50 yards. Can I recommend others take that Taiwanese HPA-kit leap of faith? Let me think about that for a moment... NO!
Note- If we believe the regulator-pressure gauge, the HPA results above came with the reg pressure set at about 9.5 BAR/1350-1400 PSI. The reg pressure is adjustable, but not externally; so would entail some amount of disassembly. As 700 FPS with 14.3 grain JSBs was exactly the performance I'd hoped for, and 40 very consistent shots per charge more than I'd hoped for, she'll stay right where she is...
For now. (Famous last words)
.22 Crosman 2240 Custom Carbine bolt-action Co2 single-shot
14.3gr JSB Express, 82F, 5 shot string (approx. 20 shots/charge at full power)- Low= 587, Hi= 607, ES= 20, SD=5, Avg= 598 FPS/11.4 FP
The Same .22 Crosman 2240 Custom Carbine converted to regulated high-pressure-air
14.3gr JSB Express, 3500 PSI fill, 40 shot powerband- Low= 696, Hi= 713, ES= 17, SD= 3, Avg= 701 FPS/15.5 FP
Smitten with the lovely 2240 Custom C02 Carbine above, but ever-wondering “what if”, it took quite a leap of faith to roll the dice on a regulated HPA conversion kit on Ebay (from Taiwan) consisting of a replacement main tube, brass hammer, regulated drop-block, and 6,000 PSI rated “titanium” chamber-tube. But after several hours of fitting, sanding, fiddling and cussing, the results are gratifyingly impressive. Whether running on Co2 or air, the little carbine consistently averages 3/4” to 1” groups at 50 yards. Can I recommend others take that Taiwanese HPA-kit leap of faith? Let me think about that for a moment... NO!
Note- If we believe the regulator-pressure gauge, the HPA results above came with the reg pressure set at about 9.5 BAR/1350-1400 PSI. The reg pressure is adjustable, but not externally; so would entail some amount of disassembly. As 700 FPS with 14.3 grain JSBs was exactly the performance I'd hoped for, and 40 very consistent shots per charge more than I'd hoped for, she'll stay right where she is...
For now. (Famous last words)
However, in some 40 years in the bicycle business I saw Japanese manufactured Schwinns (and other brands) obsolete many American models; then Taiwanese manufacture replace Japanese-made bikes once American dollars had enriched Japan to the point their bikes were no longer as economical. There was definitely an obvious difference in Japanese and Taiwanese quality; especially early on in that evolution. As Taiwanese manufacturing succumbed to American(-enrichment) dollars, Chinese manufacturers picked up the ball; again with quality-control 'growing pains' early on. 
THATS too bad. Hope Taiwan steps things up.
But you might want to check the ol' bank balance before starting...