A-ZOOM .300 AAC Blackout Rifle Snap Cap A-Zoom 300Blk precision metal snap caps are ideal for practicing trigger pulls, safety training, function testing, and safely decocking without damaging the firing pin A-Zoom snap caps are inert and completely safe Machined from solid aluminum to match SAAMI cartridge dimensions, then hard coat anodized for ultra-smooth function and long life A-Zoom patented dead cap primer insert can withstand over 3, 000 dry fires while protecting the firing pin All A-Zoom snap caps come packed in an easy to open clamshell package.