Why would you need a half-cock in an AR trigger

[AR-10]

What I mean is, how would you even get the hammer in a half-cock position unless you had the receivers open?

By barely pulling the charging handle? Why would one need to do this?

I'm talking about the WC TTU trigger:

http://militarytimes.com/blogs/gearscout/2010/02/24/wilson-combat-tactical-trigger-unit-ttu/

Educate me please, I was about to order an SSA but this TTU trigger looks like a nice single stage unit.

[Optimus Prime]

At a guess, it could help avoid a slam fire.

[AR-10]

Is that what a half-cock is for?

I seriously don't know, and I own two 1911's that both have this.

[Optimus Prime]

On a weapon with an exposed hammer it acts like a safety of sorts, locking the hammer in place to keep it from being bumped into the firing pin. On most lever action rifles it's the only form of safety.

On an AR the only thing I can think of is grabbing the hammer if the bolt goes back far enough to feed another round, yet not enough to fully engage the sear.

[5pins]

IMHO there is no need for a half cock on an AR15.

[Eric]

In the very unlikely event of a failure of the primary sear, the half-cock position will catch the hammer. As far as I can tell, there really isn't a down side to having one.

[Stickman]

If the hammer slips, the half cock position stops it from coming all the way forward and firing the weapon. Think of all the stories you have heard of AR15s doubling..... Is it needed? I would say no on the TTU, but its an extra item that Wilson Combat built in for increased peace of mind.

In all likeliness, the only time you will even think about it or know its there is when you read an article that mentions it.

The TTU isn't cheap, but it is a very nice trigger.

[AR-10]

Thanks Stickman, I just found your other article that explains the half-cock feature.

The title of the article is "Tactical Trigger Unit" so it didn't come up with the other two "TTU" tagged articles.

I really like the idea of an improved single stage trigger, even though it's a little pricey.

[Stickman]

I'll have to go back and tag that one, thanks.