I am really looking at getting a new 9mm upper. I have been looking here at the board and have read the 9mm faq. I want to know which one is more dependable in a defensive situation. Which one would you trust your life with? Quite honestly, I'm leaning towards the Oly, but I'm not sure about the SOCOM adapter. I would think that it would be possible to hit that arm and dump the mag. The Colt's (and others like it) mags are quite expensive and mostly negate the savings of the upper. Plus, I don't like having to replace anything in my lower to make it work. I probably will buy a dedicated lower for it eventually, but not right now.

So, give me your legitimate reasons that you bought either kind to help me make my decision. Thanks in advance!

I'm in the same boat. I was going to ask the same question but i'll just add to yours. I want to get a new 9mm upper and I will also be getting a lower for it. but not right know. I want a flat top and i'm going to mount my ML2 on it. So please give me some advice on which is the better system to get. Also please post any pics of your 9mm gun setup. Here's one of my first AR. It's a DPMS panther classic 16.

I have the Colt style (an ASA 9mm).  Why?  The price was right....

Oly uses cheap Sten mags... but you wonder of the Socom block.  The Colt style has expensive mags, but uses the standard mag release, nothing "new" to learn.  There is a solution to your dilema.

It is the Sten block adapter for the Colt  system.  It allows cheap Sten mags (which are notched like UZI's are notched) to work in the Colt system.


A board member's Sten block with a shortened Sten mag (for bench use).

The Oly is the simplest. BUT the upper is part of the conversion.

In a Colt style, since the ejector is in the magwell blocks you can use any upper. This is good should you wish to change your config later.

I am working on a 2 piece magblock set based on the Colt system which uses notched sten mags. I started this back in 94' but when the ban passed all efforts were on production, and all R&D projects were shelved. I have since decided to go back an complete several of these old projects.

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(Another project which is a lot more involved is a Rev 3 of my existing receiver design, this, along with a set of mag blocks will allow use of modified (but legal) Thompson M1 45 mags. This will be for 10mm & 45acp and will allow the proper function of the bolt catch.)

ProfGAB101,
    The 45 acp project would be very appreciated. I was just wondering if this would included a modification to the lower -- enlarge the inside of the magwell -- to allow the 45 acp mags to fit? Could you give us a hint to any modifications needed to the lower?

Mag availability was a really big deal for me, so I went OLY... the socom mag block is a compromise, but I've had no problems with it.  And like Kaliburz illustrated, there's some good info on how to make a modified block that will allow you to use the standard mag release with stens. I plan on making one after the holidays.

OK - I'll try to briefly describe what I will be doing.

The Std AR type receiver contacts the std 5.56 mag only in the corner areas of the magwell. There is a relief cut on each side of the magwell. In this area the width is about .900".
Also your basic AR receiver has a rib/relief area on the left side for the protruding portion on the magazine just below the cutout for the mag latch. I intend to widen that (as seen from the side) to about 1.4" and make a similar relief on the right side internally. This is not doable with existing forgings, there just isn't enough metal, the magwell wall would be too thin.

My frames are investment cast. I am going to be making another pattern mold that will have a heavier wall on the right side and the wider "rib" on the left. All the original data on my existing mold was lost in a HDD crash. I am going to have a company use a laser comparator to regenerate a 3D model of my existing mold.

This 3rd revision will accept std 5.56 mags, or with my magwell kit it will accept notched Sten mags, with a different set notched Thompson mags, also a block set for std Colt or modified Uzi mags, finally there will be a magwell kit to accept M1 30 Carb mags.

Hope that answers your questions, if not fire off an email and I'll see if I can address your concerns with better detail.

edit: I may be able to post some concept prints soon, there is still a question as to if there is a way to export from the CAD system to a .gif or jpeg. - If all else fails I may try a screen capture. But right now I am in the middle of designing a remote camera box for a 3D GPS mapping system.

My "Colt" setup on a Registered Receiver full auto for subgun competitions.
Vettman, for "defensive" situations I would personally stick with 5.56 mm.
I chose the Colt setup because of the capability to hold the bolt back after the last round with Colt mags.
NOTE:  There is a product that is soon to be released that will give the modified UZI mags the bolt hold open capability so you won't have to shell out the big bucks for the Colt mags.  I'm not at liberty to talk too much about it.  I have seen it WORK with live ammo personally.

Picture below is of the same setup with break removed and Gemtech MK9K mounted with MMag drum.

For more details, see my link below
home.cfl.rr.com/c3stuff/5_9mm/mk-9k.htm

In a situation where 9mm would be better than 223 (ie, sheetrock walls), you want the Colt setup with pinned in mags blocks.  No matter what kind of attachment/screws/cams, a mag block that is NOT pinned has a potential of coming out.  Having the mag block come out with the mag is funny in competition but fatal in a real situation.
The Olympic ejector is a weak point.  It's not "if" it's going to break, just "when".  This system is great for recreational use; but if there is a choice, choose Colt.

Amphibian,
   You have some nice stuff there! How much would a drum mag like yours set me back?

If money is no object then get the Colt style.  Otherwise Oly is the best way to go.  I've shot thousands of rounds through my Oly 9mm, with SOCOM block, and haven't had any problems.  I would trust my life with my Oly any day!  I would rather use my Oly for room clearing than my Bushy 5.56.  The 9mm is much more quiet and has practically no kick.  H&K MP5s have killed plenty of people, so don't worry about the "stopping power" of the 9mm round.  It will do just fine!
If you are worried about the SOCOM block falling out, just pin it in.  Problem solved!  Plus you will save yourself hundreds of dollars on mags.  AKs and MP5s don't have last round bolt hold opens, and noone complains about those guns!  I can handle it!

Fellas....It ain't that hard!

You don't even have to "Pin" the block permanently.  All you have to do is drill a small hole in mag release button (above the screw hole of where the latch attaches) then install a cotter pin in it.

This EASY modification will keep you from drilling unnecessary holes in your receiver, retain the mag block, and will still allow a quick conversion to a .223 upper if you so desire.

AR-Fan,
I got the drum from www.mmag.biz
I saw Mike a few weeks ago and he had only a few drums left - can't make anymore you know..  I think he wants $295 for them.  If you want one you better hurry.

Ok, a couple more questions. What is the real difference in price? I know with the Oly system I don't have to change anything with my lower (a big plus). What do I have to change for a colt system and what's the cost? Colt doesn't make a 9mm upper anymore right? So which is the best, ASA or RRA (or any others that I don't know about)?

Is one system more reliable that the other? What has broken on your 9mm upper? What things have you heard of (no urban legands please!)?

Thanks in advance and keep them comming!

Colt does still produce 9mm rifles and components - but only in "pre-ban" config for LEO rifles.  While the only Colt-produced 9mm complete rifles are LEO-only, you can find spare parts, and they could be modified for a post-ban build.  Expect to pay lots.

Least-cost for a Colt style system would be RRA, I think.  Usual parts to change for a Colt system are the bolt catch (only needed if you're using Colt factory mags, which can actuate the bolt hold-open), and the hammer, if you're using a closed-top Colt semi-auto style bolt/carrier.  You can still use the 9mm hammer with a .223 upper, but a stock semi .223 hammer won't work with a closed-top semi 9mm bolt.

My Olympic has been extremely reliable.  I've broken 2 extractors in 5k to 6k rounds.  One broke on its own around 3k, the other blew off when I had an OOB (using a brass catcher, and it bounced an empty back in the ejection port - so not really the rifle's fault).

vettman1,

ASA doesn't list an upper price only on their web site.  I'm sure the price is out there.  Their single peice block is listed at $150 (149)  The list a "kit" at $750 (as in to build a stripped lower to a 9mm).

RRA has their uppers listed from $425-475.  The mag block is listed at $150 also.  Looking at that, it's about $575 starting (if you ordered from RRA directly)

I have an ASA.  I like mine, minuse the fact that the upper isn't that nice looking. ASA took normal castings and milled off the forward assist and 223 brass deflector.  But it's not "smooth".  Then they stamped "ASA" on the area where the forward assist was.  I'd prefer a smooth side.

I didn't change anything on my lower.  And it's a factory Cav-15 lower.  I'm using the 223 hammer, recoil spring and buffer.  The hammer is curved on the top.  Garryowen said that type of hammer works on the 9mm.  I think that it was a DPMS parts kit that Cav used.  I don't care about having a last round hold open or not.  I don't like the idea of $90+ mags.  I just wanted cheap hicap mags.  First it was finding South African and modified "uzi" type.  I was sort of fine w/ buying $30-50 mags.  Then the Sten mag idea came up and the rest is history.  You can't beat $25.00 for 10 32rnd Stens and a sack.

Check out the sticky on the main page. It has lots of info on the 9mm's.

I don't have to use Colt mags in my Colt, unless I want reliability.

My Colt 9mm will work with UZI magazines, and will also work with the 40rd Argentine magazines.

The Colt is prone to "trigger slap."  I had a Colt and had a problem with that.  If you want to elimante the trigger slap, you can shell out another $200 and send it to Specialized Armament Warehouse, and they can modify the bolt carrier for you.  As far as the SOCOM mag block problem goes, you can just have Oly Arms take your Sten mags and put the conversion block on them for $25, and then you use the regular mag release button.  Then you do not have to use the SOCOM mag block, and your modified mags are still a lot cheaper than the Colt mags and about the same as the Uzi mags.  I will admit that the Oly Arms spring loaded ejector is a weak link, but most people are not aware that Dalphon will modify an Oly Arms upper and use a solid ejector and modify the bolt carrier.  They charge $75 for this modification.  I have heard about this for a while, but I have not tried it yet.  I plan on sending in a unit and will let everyone know how it works.  

Charles Tatum
Alamo Professional Arms

Have you sent in a rifle into Dalphon to get that mod yet? I'm curious how it turned out.

Interesting..... yes, please keep us posted on this.  And pics too.

Oly has upgraded the material in their wire pistol caliber ejectors in the past year or two, and it's much, much more durable.  Replacements for old ones are available from Oly cheap - or just let it break and get a new one free under your lifetime warranty.

I've yet to break my original Oly wire ejector, although I'm on my 3rd extractor.

I voted for the Oly upper because I have one, and have had absolutely no problems with it. I bought it used, and had to replace the ejector spring when I got it. I use the socom block and the $2 sten mags from Tapco. It's a ton of fun to shoot, and I've never had any problems with it. I will admit, though, that sometimes I forget to use the socom mag release, and drop the socom block out of my rifle.

FAL,  easy fix for that,  see my post above.