chambered in these guns. The round probably won't cycle a semi-auto action, so be prepared to do this manually. In addition to reloading cartridges, it is also possible to pull the bullet, remove the powder, retrim the case length, replace only some of the powder, and then reseat the bullet. This could be used to transform a .357 Magnum cartridge to a .38 Special or a .44 Magnum to a .44 Special. Just be careful to get the powder reduced properly or you'll be building a bomb rather than a cartridge. Rimfire guns have the best interchangeability. The .22 Short, .22 Short CB, .22 Long, .22 Long CB, and .22 Long Rifle cartridges can all be fired in a gun chambered for the .22 Long Rifle. About the only problem these substitutions will create is a lack of cycling in semi-auto guns. Extended shooting of shorter rounds in a .22 Long Rifle chamber might also create chamber erosion, but it would take quite a bit of shooting to do this, probably more than you'll see if you're forced to substitute ammunition. None of these cartridges can be safely fired in a .22 Magnum gun. If you're willing to go to a lot of work, it is possible to wrap these cartridges in tape or paper to "jam fit" them into a chamber of a gun, turning it into a one-shot firearm until you can send a cleaning rod down the barrel to poke out the empty--a last-ditch situation at best. There are some really dangerous substitutions that can be made from one type of chambering to the next, but these will often result in a ruptured case and escaped gas. These should be tried only if you will get killed without firing the round in the weapon. Firing a round in a different chambering is very dangerous at best. Although this could save your life if you need to fire the rifle in a combat situation, you should weigh the risks carefully before shooting. One such example is the .38 Short Colt cartridge that will also chamber in a .38 Special gun. But this isn't overly safe to fire since the bullet diameter will create excessive pressure. The .30 Mauser and .30 Tokarev (7.62mm Tokarev) cartridges will also chamber in some .38 revolvers; these smaller diameter bullets rattle down the barrel, and the cartridges often leak gas around the cylinders as well, making them potentially damaging to the gun and shooter. Other such combinations are the .223 Remington cartridge loaded into a .222 Remington Magnum rifle and the .308 Winchester cartridge loaded in a .30-06 chamber (which will sometimes work if the .308 is tight in the chamber) . The brass in either of these make-do situations will be ruined and likely jam in the chamber to boot. Most likely, it will send a stream of high-pressure gas into the action of the rifle — and your face. You might take the risk hoping for one good shot if you find your back against a wall and not firing means death. Those who ' ve mixed .380 Auto shells in with the normal 9mm Luger cartridges have probably discovered that the two sometimes can be interchanged — though not with very effective or safe results. The key factor is whether or not the 9mm pistol's extractor will lock onto the rim of the .380 cartridge. If the extractor claw does latch onto the rim during chambering, it will hold the cartridge in place for the firing pin to reach the primer, firing the round. The bullet will exit the gun with a good velocity, though it is likely there will be extraction problems or jamming in the process. (Because of the longer length of the 9mm cartridge, it can't be fired in a .380 ACP pistol . ) Those who use a 9mm Luger revolver (like those offered by Ruger in its SP101 models) might also make the .380 Auto substitution for the 9mm Luger — again with some risk to both shooter and gun. In this case, all five rounds will probably fire, though the chances of extraction problems are great. And, obviously, a steady diet of such cartridges in the gun is likely to create chamber erosion. Again, this is only a last-ditch resort. With shotguns, things are more limited when it comes to substitutions. Either .30-06 or .308 brass can be cut to remove the shoulders of the cartridge and a rim peened on the head to create a .410 shotgun shell of sorts. The .45 Colt cartridge can also be fired from many .410 shotguns (usually quite safely, depending on the condition of the shotgun) . The .45 Autorim might work in the .410 in a pinch, and peening a .45 Auto shell so it has a make-do rim might also give you something that could be fired from the .410 shotgun. Of course, accuracy suffers with bullets fired from the smooth bore of the shotgun because the bullet tends to tumble rather than spin (perhaps a plus in terms of wounding potential) . Many .410 shotguns will also accommodate the .41 Magnum, .44 Magnum, or .44 Special cartridges as well as similar rounds. In the case of the magnum loads, it's wise to pull the bullet and reduce the powder charge to avoid damage to the gun and shooter. Of course, one could argue that really smart people would avoid these substitutions altogether unless there is no other choice . The 12-gauge shotgun, like other rimmed cartridges, headspaces on the rim. This makes it possible to fire shells of varying lengths in these guns with some modern shotguns capable of