Winchester Model 100 Hammer Lock

[Bill308]

The Winchester model 100 has a part called "Hammer Lock" in the trigger assembly. It is shown on the exploded parts list. Can someone explain the operation of this part? In what mode does it engage and lock the hammer? When does it disengage?

http://www.wisnersinc.com/exploded_views/Winc-100.htm

Bill

[ogree]

It is really hard to make out anything specific from that picture, but it just may be the disconnector. Manufacturers are notorious for non consistent terminology when referring to parts of any mechanism.

[Bill308]

Thanks. The part has a slight "hook" in it that looks like it should mate with a corresponding notch in the back of the hammer, when the hammer is cocked. I'm wondering if it should be engaged, or locked, after cocking, then disengage as the first stage of the trigger is pulled?

Bill

[Cowart]

I can't answer, but here is a better diagram: http://stevespages.com/ipb-winchester-100.html

[James K]

It looks like what is sometimes called the secondary sear. If so, it is what holds the hammer cocked while the primary sear is still disengaged from pulling the trigger. When the trigger is released, the primary sear engages and the secondary sear releases, ready for the next trigger pull.

All semi-autos have some similar arrrangement to prevent the hammer from following the bolt down. It is not really a disconnector, but serves the same function. (Take a look at the M1 rifle or the Browning Auto 5 shotgun for another approach to the same thing.)

Jim

[Bill308]

Thanks for the better diagram and the great description of what the hammer lock may be and how it may operate. I've owned my Winchester Model 100 308 since it was new, in 1969, and hunted deer with it ever since. My dad gave it to me when I was 11 years old. It recently had it's first failure. It went "full auto" and emptied itself. After inspection, a couple of single shots, and then working correctly in semi-auto, it then fired while closing the bolt while loading, with the safety on. I took the gun completely apart and cleaned everything. The 3-piece bolt assembly was dirty inside, with metal shavings present, and it worked rough. After cleaning, it worked smooth. The hammer lock operation wasn't clear to me. These answers will help me inspect this. Since cleaning, it has worked fine for about 20 rounds. The gun has the safety recall firing pin installed. It will be going to a gun smith for a check before it gets used again. Can a dirty rotary bolt assembly cause problems like this?

Bill

[johnbt]

Is that the same as the trigger lock?

www.wisnersinc.com/additional_info/winchesterl_88_100.htm

"The model 100 originally had a trigger lock system to eliminate doubling, but after two years of production in 1963, the factory decided that it caused more problems than good. Because of these problems, they discontinued its use and recommended that these parts be removed from all existing rifles when they later came into a gunshop for repairs."

[James K]

A lot of information there, but unfortunately, I don't know what the trigger lock was or how it worked.

For a gun that was introduced as a wonder rifle, they sure seem to have had a lot of trouble with it. It is odd that they apparently didn't know how to make a finished barrel, then screw it in so it was lined up right. I guess there was no one left from Model 1917 days who knew how to use draw lines. So they screwed in a blank barrel and finish chambered, then finished up the barrel. Works OK but means you can't make up spare barrels.

Jim