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Posted: 12/4/2006 8:31:09 PM EDT
| I am looking at getting into the 9mm AR game and had a few questions. My first question is, other than the barrel and bolt (along with a mag block) which parts are needed to accomplish a 9mm conversion? My second question is, where can I get a 14.5" 9mm barrel with a perm attached FH to make for an overall 16" barrel? |
| You would also need either a 9mm hammer or a DPMS style hammer without a notch on the front. I don't think I've ever seen a 14.5" barrel, but you could always have a 16"cut down. I'm also not sure if anyone makes a 9mm FH long enough to bring a 14.5 up to 16. A phantom or other 5.56 FH could probably be bored out though. |
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You could have read the tacked threads at the top of the forum for far more detail, depth, and even sources of parts... But the hammer is usually a biggie in terms of converting an AR lower from exclusively 5.56mm use to 9mm use. The notch on a typical "AR 15" hammer is designed to keep it from falling with the bolt carrier and firing (one of those "remove your disconnector and it's now a machinegun" idiot things). But that notch WILL snag on a 9mm bolt and lock up up badly. A "neutered" M16 hammer (grind off the auto sear tab) or a dedicated 9mm hammer solves this, and they should both work with a rifle caliber bolt assembly as well. |
I have Rock River 16" barrels and uppers in stock. I can shorten the barrel to 14.5" or 14.7" and permanent attach almost any kind of flash hider before I ship it out. |
So.....Out of curiousity, approximately how much would you charge for a 14.5" barrel with a Troy Medieval FH in 9MM? |
You would have to pick the hardest-to-machine flash hider known to man wouldn't you? Troy brakes are hardened like a Vortex and I'm not sure I could actually clearance one for a 9mm bullet without eating my carbide tooling. Just today I broke a carbide drill bit while pinning one to a barrel!  Can I talk you into something else? |
On anything but a Vortex or Troy, that's not a problem. I just bore them out to clear as necessary. Today I opened up a 308 phantom to clear 45acp bullets for a mech-tech carbine barrel. $260 for a RRA 9mm barrel cut back to 14.5" and a Phantom permanent attached. This will use 9/16-24 threads which are superior to 1/2-28 or 1/2-36 on a 9mm barrel. 
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It's a 50% increase in barrel wall thickness at the minor diameter of the threads. If you see enough 9mm factory barrels, you will start to notice that some have a stretch mark in them about 1/2" back from the muzzle. This is from crushing the crush washer. This is ALSO why 9mm barrels come with A1 flash hiders which do NOT require indexing. If you use an A2 style flash hider and it indexes 180 out when finger-snug, there's a REAL GOOD chance you are stretching the bore in order to get the flash hider all the way around to proper index. Going to 9/16"-24 threads solves for this problem. The reason nobody makes a fuss about stretched barrels is that few people even notice it because they are not ACTIVELY LOOKING for it. Also, pistol caliber cartridges are just not known for their accuracy so nobody complains about the obviously inferior 1/2-36 thread spec causing a loss of accuracy when the barrel is stretched just before the muzzle... |
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