The Extreme Service thumb safety is the result of years of design and testing to develop a thumb safety that is ergonomically comfortable, rugged in construction and offers unique features that solve many of the problems with existing designs. It was designed specifically to benefit shooters who shoot with the thumb riding the thumb safety shelf. It also works great if you shoot thumb down. The H-D thumb safetys are also a huge plus for anyone who has less than a large hand size.
The standard width thumb shelf has an arced shape that is sculpted to meet the "plate" portion of the safety. The shelf is lowered slightly and rotated on the plate to better match up to the human hand. This makes the safety more comfortable in use over extended firing sessions. The width of the HD-451/452 safetys thumb shelf is .330" at the widest point, which makes it .075" wider than my TAC thumb safety.
The positioning of the thumb shelf also helps keep the palm of your hand in deeper, more solid contact with the grip safety, so it's less likely that you'll have a failure to get the grip safety depressed and then keep it depressed, which could render your pistol unfireable at the worst time.
The plate is made thicker than most other brands and is configured so that the safety plunger bears fully on the front of the plate, eliminating side thrust loading from being exerted against your plunger tube which can eventually loosen the tube’s mounting, allowing the plunger pin to climb over the safety's plate, potentially rendering the gun unfireable.
An ample detent pocket and radius give a positive "click" as you move the safety on and off.
The pivot shaft joins the plate with a generous radius which is crucial to prevent stress breakage of the plate/shaft joint as found on other brands.
The blocking lug has an extra fitting pad on the rear of the lug allowing the gunsmith to regulate how far down the thumb safety can swing, which keeps the safety's plate from overhanging the edge of the frame. An industry first!
The rear edge of the plate is beveled and blended where it meets the back edge of the frame so it won't dig into your thumb and web, a feature lacking on many brands.
Machined from barstock alloy steel and heat treated to GI specs; the Extreme Service thumb safety is available in matte black oxide finished carbon steel or matte stainless steel, the Extreme Service Thumb Safety is the perfect design to compliment our Extreme Service Slide Stop.