snap cap

Noun

snap cap (plural snap caps)

1. A 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
   • 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...2012, Silvio Calabi, The Gun Book for Boys
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
   • 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