use only 40 or 45 grain bullets when loading for a jet. the heavier bullets will not stabilize and i know of no reloading data for them. use only .222 or .223 diameter bullets. i have heard of people using .224 bullets in lighter weights,but i wouldn't. you can use std. small rifle or small magnum pistol primers. once you get this gun running, it will be worth all the additional trouble. they are my favorite gun to shoot. as mentioned,make sure chambers are totally dry before shooting. i use a cleaning patch with alcohol or lighter fluid works too. good luck with your jet.