>>These precision shotgun snap caps are similar in weight to standard ammunition, ideal for realistic function testing. They are precision CNC machined from solid aluminium to precise cartridge dimensions, then hard anodized for ultra smooth functioning and long life. >>These are especially useful for releasing the tension on the mainspring for long term storage of your shotgun. Cowboy shooters also use shotshell snap caps for loading and dry fire practice. >>In addition, each round has A-Zoom's remarkably durable "Dead Cap" proven to withstand over three thousand dry fires while protecting the firing pin and last over 30 times longer than conventional plastic examples.