AR 15 Mod

HAIRY

Hi, I've an AR 15 9mm upper and obtained parts for the buffer and 9mm buffer spring. For some reason, they included a 9mm hammer. Is it necessary to replace the .223 hammer with the 9mm one?

mark christian

Harry, you need to use the specific 9mm hammer in your conversion, but you don't need a special hammer spring, just use the current spring. The .223 hammer just won't work properly with a 9mm bolt.

HAIRY

Thanks for the info, Mark. As usual, you are right on. Will do the swap. Thanks again.

FWIW, I'm in the process of getting a Riesing and a Stemple 76, NIB, thanks to your earlier info. [:D][:D]

beantownshootah

quote:Originally posted by HAIRY
Hi, I've an AR 15 9mm upper and obtained parts for the buffer and 9mm buffer spring. For some reason, they included a 9mm hammer. Is it necessary to replace the .223 hammer with the 9mm one?

Only if you want to shoot 9mm rounds from your gun without ruining it. [;)]

For what its worth, I believe the different blowback design of the 9mm luger conversion cycles the bolt faster, and the lighter 9mm hammer is necessary to avoid damaging the receiver of your gun.

I know there are some hammer designs that will work fine for both .223 and 9mm guns, though I don't know if any ordinary 9mm hammer will do so.

Nwcid

My understanding has to do more with the bolt shape and how it hits the hammer.

Plus it depends on the gun. My OA was designed to use the standard hammer [:D]