Double Action Only Rationale


Factory S&W DAO Model 64 (left) could not be cocked like the Ruger GP100 (right).

Hated by Jeff Cooper, loved by police liability lawyers, double action only (DAO) duty pistols are a breed all their own.
From the late 1890s on cops were trained to cock their service revolvers to light-pull SA on the range, and reserve DA shooting for emergencies. This lingered with some departments even as late as the third quarter 20th Century, though most figured out long before then almost any line of duty shooting was an emergency, and the emphasis had to be on DA.

About half a century ago, LAPD became the first major agency to render all service revolvers DAO, for two reasons. Under stress in gunpoint situations, it was easy to unintentionally fire a cocked revolver. Second, it left officer and department alike open to false allegations of negligence the hammer had been cocked even if it wasn’t. Miami PD, NYPD, Montreal, Canada Police and more followed with DAO revolvers.

Two classic DAO 9mms: S&W 5946 (left) and SIG P226 DAO (right).

DAO Autos

The ’70s and particularly the early ’80s saw the “high capacity nine” becoming the gun of choice among cocaine cowboys and gangbangers, and police unions sought firepower parity. Fearing cocked and locked guns, chiefs who adopted autos mostly limited them to traditional double actions, which self-cocked after the first shot and required a decocking lever to be hit when the shooting ended. Cops unaccustomed to these guns occasionally fired in the line of stressful duty and forgot to decock, creating a safety problem setting the stage for negligent discharges. The solution? The DAO semi-auto.

When in the late ’80s through early ’90s the two largest municipal police departments in the U.S. finally authorized semi-autos for their rank and file, both went DAO. Then and now, NYPD’s 36,000 officers have been limited to the S&W 5946, the SIG P226 DAO, and the GLOCK with super-heavy (12-lb.) NY-2 trigger. Chicago PD’s 13,000 sworn pistol packers were initially limited to DAO hammer-fired guns by Beretta, Ruger, SIG and S&W, with GLOCKs and other striker guns not authorized until considerably later.

Beretta, SIG and S&W were the main purveyors of police duty pistols, and they all saw the rapid ascent of their new arch-competitor GLOCK — in part due to ATF classifying the GLOCK as DAO. S&W designed the one with the best trigger — light, smooth and relatively short, but lacking second strike capability because the slide had to cycle to re-set the trigger.

The DAO Beretta, the D-series, had a long but lighter pull thanks to a lighter mainspring. It had second strike capability, that is, it gave a chance to light off a misfired cartridge without racking the slide. SIG took a similar approach with their DAO variation of the P226, followed by HK with their first such variant of the USP. Unfortunately, these latter had trigger pulls most found sub-optimal.

H&K and SIG got the message which led to hybrid, quasi-DAO service pistols.

S&W Model 15 .38 Special as formerly issued by LAPD, shown cocked.
LAPD was the first major agency to go DAO with service revolvers.

Hybrid DAO Pistols

When cops stuck with DAO autos clamored for easier triggers, SIG and H&K answered with similar-but-different designs. Each bypassed the “exact same trigger pull for every shot” feature. The DAK (Double Action, Kellerman in homage to its in-house designer) had a relatively long but super-light 6.5-lb. pull from rest or full reset, and a shorter reset option needing a bit over 8 lbs. of pull, both in the same pistol. The LEM (Law Enforcement Modification) was described by the late, great Todd Louis Green as an SA auto with a long trigger take-up for the first shot. It’s been my experience H&K fans like the LEM more than most SIG fans like the DAK.

Law enforcement has trended toward the lighter weight, lower cost, and ease of shooting that comes with polymer-framed, striker-fired pistols like the GLOCK, which has been the single most popular brand. Even those have a bit of a “DAO legacy.”
We’ve mentioned NYPD and the NY-2 trigger. When St. Paul, Minn. became the first large PD to adopt the GLOCK 17, and Miami PD soon followed, both issued them with 8-lb. triggers. When NYSP became America’s first state police agency to adopt GLOCK back in the ’80s, they mandated a firmer trigger pull, and the New York Trigger now known as the NY-1 was born.

The good news is those “old school” DAO autos departments traded in for striker guns sell for comparative chump change on the second-hand shelves in the gun shops. Being DAO, they sit lonely like unwanted stepchildren, so there are deals to be had.

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