remington is the only producer of the brass,some others are loading ammo. there hasn't been any new remington ammo for about 25yrs. now. you will see it at gunshows from time to time either rediculously expensive or dirt cheap,depending on the knowledge of the seller. it takes a .222 or .223 diameter bullet for loading. i use the .223 sierra hornet bullets in my jets and have had good luck with them. even with a light handload the noise is impressive. never shoot one without ear protection. to actively shoot a jet you must reload. lubing cases is a must so it's like loading for a rifle. die set-up is critical, as is a tight mouth for the bullet to rest in. you will have to trim after 3-4 loads with anything close to a factory speed round. they are my favorite s&w gun to go play with. have owned around 25 of them over the years and still have several.