9mm M4?

[Mark K]

This question is limited to this narrow scope: I shoot pistol (fairly new to it) in IDPA and USPSA. One of the clubs I shoot at occasionally has matches were you can shoot Pistol or Rifle across the same stages. I have an AR15 that I built up, but it was really built by me as a longer range (out to 400m): 4-16x scope with short eye relief, 20" Stainless Bull Barrel, High cheakpiece stock, and heavy aluminum floating forearm. Not the sort of gun that would really work for these club matches.

I have an AR lower, stock, grip, etc, and only need an upper to complete another gun.

I currently reload 9mm and 40S&W. I don't reload rifle cartridges, and frankly don't get to a range that I can shoot rifle at much.

My question: Comments about 9mm ARs? Going 9mm would allow me to reload for the rifle, and also be able to shoot at it at the indoor range I practice at. I always intended this lower for a carbine/room sweeper. The club matches, since also pistol, only go out to about 40 yards. I am told that 9mm carbines will work out to 100m.

I do not now intend to compete in 3-gun, and if I ever did, would either build or rebuild for those requirements (I am soaking enough money in Pistol as it is.

Just looking for comments as to the ups and downs of a 9mm AR?

Thanks in Advance

Mark K

[GentlemanJim]

I love them and have built many.

I kinda like the Rock River uppers and parts

Mags can be finickey

I shoot major 9 loads in mine ...same load in my major 9 open guns...it screams compaired to standard 9mm.

Oh and dont shoot lead bullets..it gets pretty messy

Jim

[Kingman]

I was thinking about that Jim. Just dump major loads in them. I bet out of a 12" bbl or longer you can get over 1600 fps with the right bullet.

to add

Imagine a 5" m4 with a beddell ti comp on it.

Edited December 27, 2007 by Kingman

[GentlemanJim]

The 9mm acutally gives more recoil than my 223...but the 9mm bolt assembly is pretty heavy..as its a blow back design.

Its lots of fun to shoot and at a fraction of the cost of 223 and you can get a betamag in 9mm

Jim

PS I want to build a 10" gun with an integral suppressor

Edited December 27, 2007 by GentlemanJim

[warpspeed]

There is a lot of info over at AR15.com. They have their own pistol caliber section. HERE

[TMC]

I have an Olympic 9mm. It uses sten mag that are cheap and reliable and doesn't require and special parts in the lower like some do.

[Filishooter]

I have an SBR 10.5" RRA 9mm mated to a Spikes Tactical lower. I'm using the Hahn Dedicated block with modified UZI mags and new CProduct mags. Really fun and cheap to shoot! Major pistol loads aren't really required to make minor rifle. I've loaded around 8 grains of AA7 and made it. I've also shot my minor PF pistol ammo using a reduced recoil spring and it shoots very soft. For the 9mm (unless you get the bolt ramped) you will need a 9mm hammer (I hear the DMPS hammer without the spur works as well) and maybe a 9mm buffer. The gun is very accurate out to 60 yards (max distance of our range).

[chp5]

I have an Olympic 9mm. It uses sten mag that are cheap and reliable and doesn't require and special parts in the lower like some do.

+1. Olympic has a pretty bad reputation (I'm not saying it's deserved or not), but my Oly 9mm AR upper has been great.

[Keith]

I have an Olympic 9mm. It uses sten mag that are cheap and reliable and doesn't require and special parts in the lower like some do.

+1. Olympic has a pretty bad reputation (I'm not saying it's deserved or not), but my Oly 9mm AR upper has been great.

Same for me.

I even went as far as to put my Oly 9mm upper on a Hesse lower that I had lying around from way back. According to everything I've heard that combination should have just shot one round and crumpled up into the fetal position. But, I've shot maybe 1500 rounds through it and it has never hiccuped.

[Chuck Anderson]

We've been running carbine matches for years. I've seen most setups and seen problems with them all. The 9mm AR seems to be a good solution. The MP5 was another but they're still expensive and the clones didn't work well at all. Of the 9mm AR's some work, some don't. The Oly's have been surprisingly good with the only problem I know about being one broken ejector (which is surprising if you look at how cheasy it is). The Colt's have magazine issues. Some work, some don't. It normally takes the purchase of several magazines to get a couple that work okay. Colt mags are still a pain to come by and most folks use modified UZI mags.

As far as recoil reducing strategies, I haven't found much that works. Putting a comp on the end of a 16" bbl is worthless unless you specially load for the carbine. There just isn't any powder or gas left at the end of the bbl to work the comp. I've found some loads actually go slower out of the 16" bbl than they do out of a pistol. A comp on a 5" bbl might be interesting but I don't know if it would be needed with a 9mm. Keep in mind a 9mm carbine is essentially a 7 pound 9mm pistol. There just isn't a lot of recoil coming from the round. The big problem comes with the method of operation. It's a straight blowback gun and requires a heavy BCA and buffer spring. The moving mass from this is what creates the majority of the recoil.

FWIW, I'm using an Olympic Arms 9mm with the GL lower. This one uses Glock magazines. I use 33rd mags to start and the std 17 rd mags reload so fast if I can get away with it on the course of fire. The gun has never jammed and works great. I will be cutting the bbl back to about 5" and adding a suppressor.

Jim, if you're looking to suppress a 9mm carbine the sweet spot for bbl length seems to be about 5" if you want it to go subsonic. Any longer and even the commercial subsonic loads will be going a bit too fast. If you're going to use major 9mm ammo though it won't really matter.

[Mark K]

I want to thank you all for your thoughtful responses. I will certainly take them all into consideration.

Mark K

[Tom Freeman]

Here is my 9x19 AR-15.

Timers have a hard time picking up the shots so I load the bottom quarter of the mag with 124s instead of 147s.

Its a Shark SBR lower, RR 6 inch upper and mag block, C-Products mags, LaRue 10 inch rail and AAC Evolution can. Runs great, its really fun to shoot, and the Mall Ninja and CDI Factor is high.

I did forget to check the inner diameter of the handguard against the OD of the suppressor though. It took some time to get decent clearance.

[bladewurk]

Here is my 9x19 AR-15.

Timers have a hard time picking up the shots so I load the bottom quarter of the mag with 124s instead of 147s.

Its a Shark SBR lower, RR 6 inch upper and mag block, C-Products mags, LaRue 10 inch rail and AAC Evolution can. Runs great, its really fun to shoot, and the Mall Ninja and CDI Factor is high.

I did forget to check the inner diameter of the handguard against the OD of the suppressor though. It took some time to get decent clearance.

I vote Colt style! With Hahn dedicated block and Cproducts mags... Love mine. fun to shoot and esier to build since no gas tube!

[bladewurk]

This question is limited to this narrow scope: I shoot pistol (fairly new to it) in IDPA and USPSA. One of the clubs I shoot at occasionally has matches were you can shoot Pistol or Rifle across the same stages. I have an AR15 that I built up, but it was really built by me as a longer range (out to 400m): 4-16x scope with short eye relief, 20" Stainless Bull Barrel, High cheakpiece stock, and heavy aluminum floating forearm. Not the sort of gun that would really work for these club matches.

I have an AR lower, stock, grip, etc, and only need an upper to complete another gun.

I currently reload 9mm and 40S&W. I don't reload rifle cartridges, and frankly don't get to a range that I can shoot rifle at much.

My question: Comments about 9mm ARs? Going 9mm would allow me to reload for the rifle, and also be able to shoot at it at the indoor range I practice at. I always intended this lower for a carbine/room sweeper. The club matches, since also pistol, only go out to about 40 yards. I am told that 9mm carbines will work out to 100m.

I do not now intend to compete in 3-gun, and if I ever did, would either build or rebuild for those requirements (I am soaking enough money in Pistol as it is.

Just looking for comments as to the ups and downs of a 9mm AR?

Thanks in Advance

Mark K

So did you take the plunge??

[Aircooled6racer]

Hello: I am thinking of going to a 9mm AR setup. The price of ammo is going up for 223 and is going up fast. Let us know how what you decided on. Thanks, Eric

[scheirere]

I did a 9mm AR for the same reasons. Local indoor range allowed me to practice with it in the cold winter months and our local USPSA/IPSC clubs allow me to shoot the pistol matches with it during the warmer months. Mine's an American Spirit Arms, which runs the colt pattern mags. It's been incredibly reliable with all kinds of factory and handloaded ammo. I can't even guess at the number of rounds that I've put down the barrel. I think it would be safe to say more than 5000. As others have said, it's so much cheaper than .223, especially if you reload. And reloading the ammo is so much easier than messing around with .223. I've shot it in some rifle matches and didn't have any problems out to about 100yds. I imagine it could be used out further if you loaded specifically for it. Maybe light 90 gr. bullets with a hot load. Recoil is the only real negative I can think of. Not that it's uncomfortable but it's quite a bit more than .223 which puts you at a disadvantage with your splits.