Hi,

I struggle to understand firearms, and I keep reading about a 'sear'.

I did find a definition once, but it was vague and didn't really help.

Can any of the acknowledged experts here help me out?

Thanks,

hj

 

Does this help? http://en.wikipedia.org/wiki/Sear_(firearm)

I know for me, when I shoot my Colt Python .357, When squeezing the trigger (double action), when I get to the sear click, I know the next amount of pressure will release the hammer (drop the hammer) onto the firing pin.

Stewart

 

After a little digging, it did help, thanks. I'm getting the idea that this defines what a particular part does -- as opposed to a specific part name like a 'gear'.

Thanks,

hj

 

Colt's Model 1905 .45 ACP Pistol Sear Replacement - YouTube
Have a look here.

 

Parts in virtually any machine are more often than not named after their function--muffler, bearing, alternator, starter, etc...

Jason

 

Sear as it pertains to most firearms is the link between the trigger and hammer (or striker). Most semi auto and pump action models also have a disconnector that holds the hammer upon returning to a cocked state until the trigger is released.

 

Most conventional firearms have a trigger, a hammer, and a sear. I assume you understand what the trigger and the hammer do, the sear is the intermediary piece that catches or latches the hammer in the cocked position until the trigger acts upon it to release it. A lot of sears are mechanically designed as a lever with a pin as the fulcrum. The trigger pushes on one end of the lever causing the other end to release the hammer. The surface where the sear and the hammer meet determine a lot of a trigger's creep and break characteristics, which is why you read a lot about polishing or changing the angle of the sear to improve a trigger.

 

That is true, but I can usually find some description of how they operate.
Still, good point.

Anyway, the light is starting to get a little brighter. (when it comes to mechanical, I'm good at electronics )

Thanks to all,

hj

ps -- reps to all that I could!

 

The "sear", is the latch point, or catch, or interface, between the trigger and the hammer. A sear might be an individual piece of metal, but it is only called that because it performs the function of latching and releasing the hammer upon firing. Some firearms don't have a unique piece called the sear, because the hammer and trigger interact directly. In that case the sear is the interface between hammer and trigger. Of course there are infinite possible arrangements of trigger design. As far as I know, all mechanical triggers will have a point of sear. There are electronic exceptions.

The sear is where work is done to adjust or improve a trigger. As in "stoning the sear".

In the picture below, you can see the hammer and sear arrangement in a Colts 1911 semi-auto. The half-moon shaped piece is called the sear, but more importantly, the sear is the point where that piece contacts the hammer, and holds it cocked. That point is called sear engagement. A lot of magic happens right at that point of contact when the right gunsmith/magician is at work.

In that photo, the trigger components are not shown, and in fact the hammer and sear are pinned to the outside of the frame, so that the gunsmith can see his work. You can buy or make tooling jigs that simulate the pin locations so that you don't have to work directly with the gun frame.

 

It's what happens when hot brass from your AR goes down your shirt. It "sears" the skin.

Sear.

 

Quit shootin' it southpaw, duh!

 

I thought that was just when the brass from the shooter next to you goes down your shirt, under your arm, etc. I still have marks from the AQT at Appleseed over a year ago-

I was always told the sear was to prevent the hammer from falling again until the trigger was released, preventing automatic firing. That's why a sear failure usually results in the gun just going nutso full auto.