snap cap

plural snap caps

1. engineeringA dummy round of ammunition used to check ammo feed and other mechanical problems.

   1187. B. Lilly. Improvements in the construction of "snap caps" or "nipple protectors" for firearms. Dated May 12, 1863.

   1863 December 18, The Mechanics' Magazine, page 889

   2 more examples

   Snap caps are dummies (no powder, no primer, no projectile) shaped like the ammunition for a particular gun. They're supposed to provide something for the firing pin to hit during dryfiring, so the gun's lockwork doesn't have to absorb this impact. It's a fine idea, but not all snap caps are made right.

   2012, Silvio Calabi, The Gun Book for Boys

   However, it does no harm (and may prevent damage) to use snap caps - dummy rounds which are inserted into the chamber to soften the impact of the firing pin.

   2014, MAssad Ayoob, Gun Safety in the Home, page 124

2. A cap or cover that snaps into place.

   Development of the snap cap for Bufferin pinpoints the Bristol-Myers Products approach to these problems.

   1966, Package Engineering, volume 11, page 66

   2 more examples

   After centrifugation, the top dense band (out of three formed following ultracentrifugation) contained the purified oocysts, which were removed using a pipette and placed in 15 mL polypropylene snap cap tubes.

   1997, Gordon R. Finch, Effect of Various Disinfection Methods on the Inactivation of Cryptosporidium, page 10

   The shampoo bottle closures included a screw cap closure considered to be the most vulnerable during use, a flip or snap cap with a circular orifice considered to offer the greatest degree of protection, and a flip cap with a slit orifice whose protective abilities were unknown at the time.

   2011, Nava Dayan, Formulating, Packaging, and Marketing of Natural Cosmetic Products