Why does a AR15 hammer have the notch at the top?

Is there a rounded hammer for sale out there?

If you took a M16 hammer and ground the full-auto notch off would that hammer be legal to use in an AR15?

To lock up the works if the disconnect wwere to fail or happen to be removed on an AR.


Yes, but usually found at the gun show, seller has cut off the M16 auto sear lug.


Yes, the ability to operate in auto mode has been removed.

The notched hammer does not effect anything in operation of your gun unless some of the parts are not working properly then the notch will prevent your gun from double shooting, and will lock your bolt part way open. If this is happening it's due to worn parts not the notched hammer.

Also the notched hammer will not work in the Colt style semi auto 9mm guns. You need a rounded hammer or a 9mm hammer.

Yes a de-hooked M16 hammer will work, but just don't do it for full auto reasons.

Thanks for replies.

It just looks to me like the notched hammer would dig into the bolt, but if that isn't the case I will no longer worry about it...

DPMS will happily sell you an un notched hammer, which is actually an M16 burst fire piece with the sear trip lug removed.  I know this because it was on the DPMS assmbled lower I just bought 2 weeks ago[:D]

The word I keep getting on this site and elsewhere is that Colt and some of the aftermarket makers are phasing out that cutaway carrier and notched hammer thing anyway.  About damned time.  Never was a federal requirement for the AR. Just some BS somebody at Colt dreamed up 40 years ago, and all the aftermarkrt people copied.[;D]