In the quest for 12 foot ponds of energy, I decided after all the modding to my Crosman 1322, that I would over pump and see what I could generate in terms of power. I originally expected that I was going to have to increase the barrel length to get to 12 foot pounds of energy. As it turns out, it is achievable without a longer barrel, some increased air cylinder volume, and a steel breech. But just barely.
Over pumping resulted in shot strings that were over 600 fps with 14.3g Crosman premier domed and pointed, pellets. My highest that I could record is the 618 FPS.
The sweet spot for consistent shot strings for my pistol now lies around 16 pumps, for over 580 fps. I’ve taken rabbits past 65 yards with the Crosman 1322 in Wyoming winds, and I have no ethical or moral qualms with the dispatching energy at even greater distances.
In ideal conditions, I’d like to use a rest, or shooting sticks, and try to take a rabbit or grouse, past 100 yards. I’m still toying with the idea of a few more inches of barrel length so I don’t waste air, but am not sure I want increase the gun size and decrease the backpack portability of the pistol.
Tags: 12 fpe, 1322, crosman, mods Comments
Hello Benjamin. I’ve very much enjoyed your numerous postings regarding the Crosman 1322. I’ve very recently purchased my first airgun, the 1322. I’m interested in the various performance modifications which can be achieved with the 1322. You mentioned increasing the volume of the cylinder/valve. Will you please tell me where I can find instructions for that procedure, and instructons for any other modifications that will improve power and accuracy with the 1322. Thank you!!!!!!! [p.s. ~ Benjamin, please send your answer to my email address, because I don’t know if the Sportsman’s Magazine will notify me when you post an answer here in the comments section. Thank you!!!!!!!!!]
Hi John. The process is conceptually very simple. Removing the cylinder that stores pumped/compressed air, and then grinding out material so that the inner diameter is larger. Becareful not to over do it. You can see how others have done modifications at https://www.gatewaytoairguns.org/GTA/index.php?topic=156865.40
I actually have more volume of air than gets used in a shot. Meaning the short barrel pushes the pellet past the muzzle with a huge volume of air still exhausting, but not seemingly doing a lot of work. Adding a longer barrel would likely increase FPS some more. Just over pumping a 1322 with a steel breech will get more power, adding a longer barrel will get velocities up, and increase FPE.