Combat City USA, a gun range in Florida, is offering you the chance to shoot your friends with real guns. They allow you to bring your owns guns to use in their airsoft arena. They swap out a number of parts to convert them to the Ultimate Training Munitions (UTM) Man-Marker Round (MMR) system or the Simunition system. In the video below the rifle is being used with UTM rounds and the revolver with Simunition rounds.
Between the two systems they can only accommodate the AR-15, Glock 17/22/31, H&K USP, SIG P226 and .38/.357 caliber revolvers, not any gun as reported by CNN.
THe UTM MMR round design is very clever. Each round contains two primers. The first primer is used only to detonate the second primer and to cycle the action (using pressure inside the cartridge to push the sliding base backwards) and does not add any energy to the bullet. The smaller second primer is used to propel the bullet and does little or nothing to cycle the gun. A conventional blank round capable of cycling the action would propel a plastic bullet at potentially lethal speeds.
Unlike a paintball the bullet does not need to break apart to mark the target. When the bullet hits its target, the “inertia applicator ball” pushes the marking wax through the plastic shell onto the target. The wax can easily be washed off clothing.
The UTM round has about 4 joules of muzzle energy compared to a paintball which has 10 – 14 joules (depending on the gun) but the joules per square inch is much greater for a 5.56mm UTM round which has a cross section about 1/10 the size of a 0.68 caliber paintball. In other words: at close range it will hurt a lot more than a paintball.
[ Many thanks to gunslinger for the tip. ]