Pros: All metal and very rugged.
Cons: More expensive then other types
A common form of firearms practice is what's known is "dry firing." Basically this means practicing with an unloaded firearm so that you can improve your trigger pull and familiarize yourself with the firearm when you aren't actually at the range.
Snap caps are fake cartridges that you insert into the chamber while dry firing in order to protect the firing pin. They usually contain a spring where the primer would be on a live cartridge to absorb the impact of the firing pin and reduce the chance of damage to the pin. While nearly all modern firearms can be dry-fired with only a minimal risk of damage, using a snap cap does reduce the risk even further.
There are snap caps available in almost all the common rifle, pistol and shotgun calibers. Each snap cap type should only be used in that caliber firearm. One nice thing about the A Zoom Snap Caps is that they are clearly marked with the caliber designation on the body so that you won't mix them up with other caliber snap caps.
Snap caps can also be used when at the range to help you practice malfunction drills. The only way to really learn and remember how to make a malfunctioning firearm work quickly is to purposely cause a malfunction and then clear it using the correct technique. Since snap caps do not contain any propellent or have a primer, when the snap cap is loaded into the chamber and the trigger is pulled, the gun will not fire. This forces the shooter to use the correct technique to fix the problem.
As a firearms instructor I regularly use snap caps both for my own practice and with students that I teach. I have used several different types of snap caps and have figured out which designs work best.
Unlike other snap caps,which may be all plastic or have plastic parts, the A Zoom snap caps are all metal. The A Zoom snap caps are formed in one piece so they can not break or seperate. They do have an internal spring to absorb the impact of the firing pin on the end of the snap cap.
The fact that the A Zoom snap caps are all metal is advantage when performing malfunction drills. I have had pieces of plastic break off of plastic snap caps in the past. One time a small piece of plastic from a snap cap got wedged in the slide to the point where the gun had to be dissassembled before it could be fired again. Needless to say, this is not good.
I have the A Zoom snap caps in .45 ACP and I regularly use them with my classes. I've found they always work as advertised. They load into the magazines easily and chamber into the gun with no problems. When a proper "Tap-Rack-Bang" malfunction drill is performed, they eject from the gun with no problem. I've yet to see an A Zoom snap cap get damaged beyond the occasional light scratch.
The only disadvantage of the A Zoom snap caps is the cost. Piece for piece they are more expensive then the all plastic or plastic and metal snap caps that I have also used. This is a concern because even if they do not get broken, snap caps do tend to get lost over time if they are not immediately found after they are ejected from a firearm during a malfunction drill.
Still, even with the higher price, the A Zoom snap caps are probably the most durable on the market. When I use them I like knowingly that they will protect the firearm and won't leave any plastic debris in the mechanism.