School me on 9mm AR's.

[Tronster]

I've got a HiPoint 9mm carbine (meh) and while it shoots ok, it lacks any refinement and the sights need constant adjustment.
I'm not really interested in a folding plastic KelTec, nor shelling out $900 for a Beretta CX4.
So I've been toying with the idea of converting/building a 9mm AR, unless there is another dedicated 9mm carbine I'm not aware of.

1) Mags are typically Colt/Uzi or Glock mags. Which one is better for reliability in the AR? It appears only dedicated lowers can use Glock mags.

2) Dedicated lower or magwell block? I see Hahn has several different magwell conversion blocks for $170-200 (typically using Colt/Uzi mags), or there are dedicated lowers from Lone Wolf / New Frontier / Quarter Circle 10 for both Colt/Uzi and Glock mags.

3) Wear on the hammer pin, and AR10 springs. I've read about how blowback 9mm are hard on the hammer pin holes getting wallowed out, and some shooters using AR10 springs to slow down the bolt speed. Any truth to this?

[Ivan45]

A JRC might fit your needs

[TooFewGuns]

Have you looked at Rock River?

[Bitter Bastard]

I've got a HiPoint 9mm carbine (meh) and while it shoots ok, it lacks any refinement and the sights need constant adjustment.
I'm not really interested in a folding plastic KelTec, nor shelling out $900 for a Beretta CX4.
So I've been toying with the idea of converting/building a 9mm AR, unless there is another dedicated 9mm carbine I'm not aware of.

1) Mags are typically Colt/Uzi or Glock mags. Which one is better for reliability in the AR? It appears only dedicated lowers can use Glock mags.

2) Dedicated lower or magwell block? I see Hahn has several different magwell conversion blocks for $170-200 (typically using Colt/Uzi mags), or there are dedicated lowers from Lone Wolf / New Frontier / Quarter Circle 10 for both Colt/Uzi and Glock mags.

3) Wear on the hammer pin, and AR10 springs. I've read about how blowback 9mm are hard on the hammer pin holes getting wallowed out, and some shooters using AR10 springs to slow down the bolt speed. Any truth to this?

OK, a few different points here. I own a 9mm AR-15 SBR built from a Colt 635 SMG parts set. It may be the most fun gun I own. Accurate, reliable, cheap to shoot, low recoil, etc.

So, here goes, this is my opinion based on quite a bit of research a few years ago plus trying to keep up with changes over the years.

Mags - I'd recommend just going with Colt-style mags. Quality ones can be had for about $25-30. Metalform has probably the best reputation. C-Products are also good but in my experience, not as smooth to load or use. I've heard nothing but good about Brownell's magazines but not sure if I've tried one or not. Colt mags were made by Metalform, then by C-Products, and I think now by Metalform again. Colt-style 9mm mags are basically Uzi mags with a different magazine catch location, the rear of the feed lips opened up to allow for use of the bolt hold open, and a new follower to activate the BHO. If you don't care about the BHO, converting an Uzi mag is as easy as cutting a new mag catch in the right location. The mag would still work in an Uzi but may hang up on the higher Colt notch as you insert it into the Uzi. Ehh, I just use Metalforms and be done with it. I really like the idea of Glock mags but you need a bolt modified slightly also. Ehh, again, I just went with the proven Colt system although from what I hear, the Glock lowers work just fine as well. A mag loader is very very helpful as the mags can be very difficult to load.

Mag blocks - My lower is an older Rock River with removable mag block, but it kept shifting every so slightly up or down and would lead to jams. I said screw it and drilled a couple holes and just pinned it in place. Theoretically, I can still remove it because it's just a couple roll pins, but really, with lowers so cheap, I didn't/don't see the need. Having a dedicated 9mm rifle that just plain works in addition to a 'normal' 5.56 rifle was well worth the extra tax stamp and few extra parts to me. I can tinker with the best of them but I'd rather spend the time shooting than swapping parts or clearing jams. I think one of the dedicated, one-piece 9mm Colt style lowers would be the way to go today for a new build. The blocks work from what I've heard but they are not as trouble free, in general, as a dedicated lower.

Wear on the lower - 9mm lowers ARE hard on the hammer and trigger pins. That is why Colt uses stronger stainless steel pins instead of 'regular' steel ones. I think most stories of wear on lowers is greatly exaggerated. I read of one guy who was using the aftermarket anti-rotation pins to try and save any wear on his lower and had one break. The extra contraptions kept the broken pin in place, leading to more damage to the lower than a simple broken pin would have, which would have likely led to jams, troubleshooting, and the discovery/replacement of the broken part. To help mitigate wear on the pins, people 'ramp' the bolt carrier (the bolt really since it is all one piece on a 9mm) which helps reset the hammer a bit more gently. Even Colt is now doing this. Mine is pre-ramped and I don't worry about it. It works fine and even shooting it frequently it still won't ever see the use/abuse a SMG would. That makes me a bit sad but is reality for current gun laws and my budget.

There are some other considerations with the 9mm system but a properly tuned gun will just run and run. I've had ZERO problems with mine once I got my mag blocks to stop moving. One somewhat frequent issue is broken bolt catches. I've not had that issue but there are cheap fixes for it such as changing buffers, buffer lengths, etc.

I have my gun pretty much as close to a stock Colt SMG as possible and have no problems. Many issues people talk about arise from wanting to run a different buffer, different buffer spring, barrel length, etc. I think the current Colt 6950's and 6951's are a great crop of guns. I prefer my 10.5" barrel as it handles well and doesn't look goofy with the longer barrel.

Hope this helps, good luck!

Bitter Bastard

[Tronster]

That was exactly the info I was hoping for! I was concerned that a mag block could shift around and you confirmed that. I'm not really worried about having a last round BHO; this is just a fun range toy. I have read about how many of the 9mm bolts today are ramped to help lessen the impact on the hammer pins. As far as mags, I've actually got a stash of 15 round and 33 round mags for our Glock 19 already, so I think it only makes sense for me to stick with a Glock mag dedicated lower instead of trying to convert one of my nice Mega lowers to Colt mags. Thanks for your input Bitter Bastard!

[mahnster]

I have one with a dedicated Glock lower. It is one of my favorites to shoot. It is a DDLES which are now made by QC10. There are several other companies now coming out with Glock lowers.

By the time you buy a quality mag block and standard lower receiver it is basically the same price as buying a dedicated lower. Then you won't have to worry about any mag block issues.

The bolt will have to be modified slightly to use Glock magazines. I did mine myself, perks of being a machinist.

They can be hard on hammer pins. Several companies offer a spacer to go in the buffer tube to prevent the bolt from going too far rearward. Other companies offer a longer and heavier buffer to do the same thing while adding mass that helps smooth it out. It definitely helps to use a heavier buffer. I made a stainless plug to put in front of a standard buffer instead instead that accomplishes the same thing.

[mmcnx2]

If you were going to buy a finished rifle in 9 that took glock mags what would you recommend. Budget not being the biggest concern but also don't want to put $1000 in to a range toy.

[mahnster]

If you were going to buy a finished rifle in 9 that took glock mags what would you recommend. Budget not being the biggest concern but also don't want to put $1000 in to a range toy.

Not sure if anyone is offering complete AR 9mm rifles that take Glock magazines. There are several companies making lowers but not complete rifles that I have seen.

Nothing special about building them compared to a regular AR15 but uses some different components.

Kel Tec Sub2000 and Just Right Carbine take Glock magazines.

[Ron Burgundy]

JP GMR13 uses Glock mags. It's what I'd like to own.

[mmcnx2]

Any dealers around here hand the just right brand?

[Tronster]

The JP GMR sure looks nice, but I don't know about $1500 nice, and their stripped glock mag lower is $400! A complete RR is $1200 and stripped lowers are still $300. The JR carbine seems to have iffy mixed reviews and doesn't share many parts with AR's.

I just don't get why 9mm carbines cost so much. The HiPoint cost $189 and there's not much engineering involved, so it shouldn't cost $1000+ to make an AR run 9mm, esspecially with the glut of AR parts out there. The only proprietary parts are the barrel and blowback bolt, and some way of attaching a mag.

[Bitter Bastard]

I just don't get why 9mm carbines cost so much. The HiPoint cost $189 and there's not much engineering involved, so it shouldn't cost $1000+ to make an AR run 9mm, esspecially with the glut of AR parts out there. The only proprietary parts are the barrel and blowback bolt, and some way of attaching a mag.

Depends on the maker. For Colt - barrel, flash hider, bolt, ejector, extractor, firing pin, upper receiver, ejection port door, gas deflector, buffer, buffer spring, bolt hold open, mag block, hammer/trigger pins. Probably the front sight height but I don't know that for sure.

A lot of other makers use the same upper receiver as a 5.56 but most of the other parts are still proprietary. But smaller runs of parts by fewer makers usually results in higher prices.

The JRC carbines just seem hinky to me. They do get some good reviews but some bad ones too. I've handled them but never shot them.

Good luck!


Bitter Bastard

[linksep]

I just don't get why 9mm carbines cost so much. The HiPoint cost $189 and there's not much engineering involved, so it shouldn't cost $1000+ to make an AR run 9mm...

I'm with you but we must be in the minority. Hi-Point and Kel-Tec seem to be the only players in the inexpensive pistol caliber carbine game (MSRP <$750). I mean it can't be hard or expensive for an OEM to add a stock and long barrel to a Glock or Sig P226/P229 or Beretta 92 or S&W M&P 9/40/45 or 1911... Yeah there are aftermarket conversions available for Glock & 1911 but really why come out with a CX4 Storm or other unique design when almost all you really have to do is add a stock and long barrel? (I guess there is the non-fixed barrel issue to deal with for most or all of those pistols, but I would almost consider that to be a "tweak" rather than a "re-desogn" for a large OEM.)

ARs run .308 and .223 and .22lr with very little issue but for some reason functioning between .223 and .22lr becomes difficult?

[Bitter Bastard]

I'm with you but we must be in the minority. Hi-Point and Kel-Tec seem to be the only players in the inexpensive pistol caliber carbine game (MSRP <$750).

What about Cobray M11 carbines? Century Uzi? Wilkinson Linda Carbine? Marlin camp carbine? The Kel-tec and JRC have already been mentioned. The Beretta carbine. Maybe a Calico if you find a good deal. Or a used AR-15 in 9mm on a good day. And probably some semi-obscure subguns made by Century or small shops over the years and rebuilt as semi auto carbines - like a Sten or Sterling maybe. These can all be found for around $750 or less if you don't mind a used one. I'm sure I'm missing some also, there have been lots of smaller mfrs over the years and those are still floating around the secondary market.

As long as I've been into guns, there have always been 9mm carbines ranging from cheap (M11) to expensive (HK-94). I think the market is fairly small or there would be more choices. As it is, there are some very good guns in that space but maybe not just as many choices as in other markets, like 9mm handguns.

And if you really want to expand your horizons and wallet, maybe an AUG or Tavor with a 9mm conversion kit.

ETA: Oh, and one reason why there aren't many options between .223 and .22 is lack of magazines that fit the AR-15 mag well. Most .45ACP mags are too wide. And for 9mm, Colt basically went with Uzi mags that did fit just fine. And really, other than .45 and 9x19, what else is there? Kidding, but those are by far the most popular pistol rounds in America. I think it was Eugene Stoner that said something to the effect that anyone can design a rifle, it takes a genius to make a reliable magazine. So many conversions rely on existing magazines.

Good luck!

Bitter Bastard

[Randygmn]

OP mentioned the Beretta CX4. Great gun, by the way. They can be had in the $700 range. Half the price of these dedicated AR's, but yes, a different manual of arms. There is a weakness in the gun, it's trigger pack. There are upgrades, if needed.