MPRI has a BEAMHIT laser marksmanship training system  that employs a laser which mounts onto the user's regular duty weapon. The laser emitter, called a LTX-Z, inserts into the barrel of the gun and fires when the user pulls the trigger. Obviously, you want to be fairly certain there's no round chambered, although you can use the setup with a fully loaded magazine.

The targets are electronic; they have projection based targets and physical targets that record the hit. Some of these are pop-up targets that ca be controlled remotely or programmed to pop up at designated intervals. When the pop-ups are hit, they fall down. These are called Mini-RETS: Remote Electronic Target System.

If you want a more realistic experience, MPRI has a Safe Shot solution that employs a lead-free, alcohol based blank that gives 90% of the recoil and about 50% of the sound of a live round. The system includes a replacement barrel containing a laser, which, when in place will allow only the Safe Shot ammo to be chambered. It uses standard magazines, and there's no concern with ventilation, so it can be used indoors or out.

There is a similar system for most patrol rifles, where a caliber-specific rod inserts into the barrel of the weapon.