Laser Dry Fire Hardware
Laser Ammo and LaserLyte both sell cartridge inserts that can be used with your existing gun. However, reviews on Amazon suggest QA issues exist with products from both companies. Many reviewers state that items are dead on arrival or break after very little use, however both companies appear to have outstanding customer service.
Laser Ammo seems to be the more convenient of the two because their adapter system allows you to use a trainer with multiple calibers instead of forcing you to buy a trainer for each caliber. For what it's worth, the creators of ShootOFF use Laser Ammo products and have had no problems other than batteries that were dead on arrival. Order new batteries from Amazon (e.g. http://www.amazon.com/gp/product/B00ILXZ4SQ/ref=oh_aui_detailpage_o01_s00?ie=UTF8&psc=1) at the same time you order a cartridge.
Laser Ammo + ShootOFF Review:
"I've been using the ShootOFF program with Surestrike Laser Ammo's .40 adapter for my Glock 23, and .308 adapter for my DPMS LR-308. I've dry fired approximately 600 times using the same base 9mm laser round for both firearms. The combination has been a great way to practice and provide entertainment without the cost and time spent going to a gun range. Obviously it's not a perfect substitute for live fire training since there's dramatic difference in accuracy without recoil, but it's still an effective alternative. Utilizing ShootOFF, I've been able to notice subtle bad habits in firing technique and make adjustments to improve. The only issue I ran into was with the Laser Ammo .308 adapter. The outer rim to the tip of the adapter was slightly larger than it should have been, preventing it from fully seating in the chamber and jamming the bolt. After contacting the manufacturer and following their recommendation, I polished down the over-sized area with a dremel tool which got it working perfectly. Overall, ShootOFF with Laser Ammo has been an excellent way to get in some practice, teach others how to properly handle a firearm, and have some fun without spending a lot of time and money to do it."
Click the preview above for a brief video demonstrating a Laser Ammo Infrared product with ShootOFF
The SIRT Training pistol comfortably supports semi-auto dry fire and doesn't come with the QA baggage, but some versions are very expensive and only comes in Glock models. There are several levels of training pistol available, with weight realism ranging from exact to a Glock 17 to several ounces lighter in the less expensive polymer versions. Next Level Training also offers a resetting AR-based laser kit, if rifle practice is desired.
Laser Shot sells laser trainers in a number of form factors if you're looking for an alternative to the Glock trainer from SIRT, but they provide essentially no information about their trainers. The products are generally priced comparable to SIRT's trainer, but it is not clear that they achieve feature parity.
AIMTech makes bore inserts for handguns and shotguns, and barrel mounted systems for AR-15 and AK-47 platforms. AIMTech claims to have notably better battery life than other offerings.
Review: http://www.thetruthaboutguns.com/2013/12/foghorn/gear-review-aimtech-laser-training-system/
The cost claims in this review seem to show ignorance of the larger laser dry fire training market.