hammerless

From his coat pocket Britz produced the weapon, a gleaming steel revolver of the hammerless variety.
The Substitute Prisoner|Max Marcin
The time of its construction was before the days of the hammerless.
Camp and Trail|Stewart Edward White
This could be still further improved upon by making it hammerless; that is with an internal hammer.
The Modern Pistol and How to Shoot It|Walter Winans
In 1871 T. Murcott patented a hammerless gun, the first to obtain distinct success.
Encyclopaedia Britannica, 11th Edition, Volume 12, Slice 6|Various

A hammerless revolver, a short time ago, would have been considered an unsafe weapon.
The Modern American Pistol and Revolver|A. C. Gould

British Dictionary definitions for hammerless

hammerless

/ (ˈhæməlɪs) /

adjective

(of a firearm) having the hammer enclosed so that it is not visible

Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012