AR question: Which hammer can run 223 and 9mm

[ForceTA308]

My plan is to build a 9mm AR pistol and then go the SBR route from there. I'm working on the lower and know that you need a 9mm hammer for it to run well (or at all). My question is, is there a hammer that can run 9mm and 223 without having to switch them out if I swap to a 223 or other cal upper? I know that a 223 specific hammer can't run 9mm but is the reverse possible? I'm trying to see if there is a LPK available that includes a hammer that can run both, otherwise I can get the hammer separate.

I know I'll need the magwell block and buffer also.

If it helps, I found this on another forum and the poster said that you could run both 223 and 9mm with this style of hammer. Can anyone confirm this and let me know what style this is if so?

 

[rvb]

that will work. That's an M16 hammer w/ the auto sear hook [mostly] filed off. A 9mm hammer will also work for both 9mm and .223. There are a couple vendors making M16-style hammers w/o the autosear hook. What's important is the top of the face of the hammer be rounded, not notched as many AR hammers are. Many aftermarket hammers and trigger groups accomplish this.

-rvb

 

[jrainw]

M16 hammer will run both, find a pic of an M16 hammer and get a semi auto hammer with the same profile but no auto sear hook. I have run M16 and Geissele SSF triggers successfully with 9mm, .223, and 22lr drop in kits only changing the uppers.

 

[OneBadV8]

Also, if you run the CMMG Ramped 9mm Bolt Carrier group, you can run a 223 hammer in it.

 

[ForceTA308]

Great, so it sounds like an M-16 hammer without the auto sear hook is the way to go. Thanks for clearing that up fellas.

 

[DaKruiser]

A standard AR hammer and a ramped 9mm bolt is the ideal way to go.

You want the bolt ramped to prevent hammer pin and reciever wear, the 9mm bolt can put allot of force on the hammer that transfers to the pin and reciever resulting in an egged hammer pin hole over time.

 

[ForceTA308]

Copy. It looks like I would be looking at either a RRA or CMMG ramped bolt.

While I have your eyes, I have one more question. As far as the magwell adapters it looks like my best options are Hahn, Spikes, RRA, CMMG, ProMag,...? Any that I'm missing that you would recommend? Which one of these would be your choice based off performance and magazine availability?

 

[DaKruiser]

I run a Hahn and metal form mags, I have a few friends that run Spikes mag blocks with spikes mags. If I was to do it again, I would run all Spikes as well.

We all run CMMG ramped bolts with standard hammers.

 

[Sling10mm]

That's awesome info on the CMMG bolt carrier. I haven't shot my 9mm upper in years because I just didn't want to mess with changing out the hammer. The wife is going to hate this though...

 

[OneBadV8]

I run a Hahn and metal form mags, I have a few friends that run Spikes mag blocks with spikes mags. If I was to do it again, I would run all Spikes as well.

We all run CMMG ramped bolts with standard hammers.

For the record... I'm pretty sure the Spike's mags are just metal form mags with a Spikes end plate.

 

[DaKruiser]

That's awesome info on the CMMG bolt carrier. I haven't shot my 9mm upper in years because I just didn't want to mess with changing out the hammer. The wife is going to hate this though...

If you already have a non ramped 9mm bolt, it might be cheaper to have a gun smith ramp the bolt you have.

 

[jrainw]

Pretty easy to ramp a 9mm bolt, I did mine several years ago. I just cut it to be similar to a 5.56 bolt and it is much smoother and easier on fire control parts.