I'd like to see some company produce some special .38 / .357 chamber inserts that take a primer on the back end, and have a .177" bore into which you'd load a .177 lead pellet of your choosing. No gunpowder needed. The purpose of this would be to have cheap, low-noise, low-powered training and backyard plinking ammo. These sub-caliber inserts would be good for practicing drawing quickly and getting a hit on the target ASAP. They wouldn't be good for pinpoint accuracy, but minute-of-bad-guy. I'm not sure if they'd even need to be rifled. Let's say "yes" but with shallow rifling, so that it doesn't take a lot of pressure to push the pellet down through that short (1") rifled bore. You could reload them yourself with simple hand tools. A little stand and shell holder, a hand-activated primer press a polymer dowel and a tap hammer to seat the new pellet, etc. I'd probably want to have 50 such chamber inserts, so that I could reload and shoot several cylinders full of these before I had to stop shooting them (or take a break and spend some time reloading them). Unlike dry fire practice, this would give you a real projectile that impacts the target to give you feedback about your aiming /pointing ability. For semi-auto calibers, they could make the chamber inserts with a long rounded-tip section to replicate the profile of a live round. I guess you'd be limited to just drawing and firing a single round, if you want to keep the training realistic. Because if you wanted to take a second or subsequent shot, you'd have to reach up and manually work the slide. You could have your magazine loaded with these dummy rounds, pre-loaded with pellets. They should feed and extract and eject fine, as long as you pull the slide back by hand. I'm thinking this product would appeal more to wheelgun shooters, not only for the ability to shoot the weapon in the normal SA/ DA mode, but also because if you are working outdoors over grass or mulch, you may lose some of the cases that are ejected from the semi-auto, when you're not paying attention to where they fall, and you're instead focusing on your target.