Pistol Caliber Uppers

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SundownRider

New member
Hello All!
Looking for advice. I am looking to get a 9mm or .40 cal upper for my AR platform. It is difficult to shoot rifle calibers where I live so I want to be able to practice with the platform.

I know RRA, CMMG, and Olympic Arms make complete uppers, but I have been having a hard time finding information.

Which one can I just stick on my lower and be good to go?
Which one does not require me to modify magazines?
WHich one is the most reliable?

ANY help is appreciated.
 
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RWBlue01

New member
I have been interested in a 9mm upper for a while. I am not sure why finding what I want is difficult.

The best conversations I have found about this subject are on Glocktalk and AR15.com.

You will need to decide if you want a dedicated rifle or a switch hitter (223 and 9mm). The switch hitter is harder to build. You have to swap out the magazine block, but I am getting ahead of myself.

Being that I want a SBR 9mm and I already have a SBR AR.....I want a switch hitter. Finding all the parts and having the money and .....well it just hasn't happened.

Here are some key points for discussion.
The hammer in the LPK matters?
What magazines are available and reliable at this point in time?
Is there a place for one stop shopping?
Lets talk bufffers and springs?
What is the optimal length for a SBR in 9mm using 147gr bullets (thinking just subsonic)?


I assume someone with more knowledge than I will be along at any time, but if not I will try to fill in what I think I know.
 
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rjrivero

New member
Make sure the hammer in your AR is a smooth hammer. The DPMS one works fine but the ones with the hook can catch the bolt on the 9mm.

The mag block can be a top loader or bottom loader. If you plan on switching back and forth between 9mm and .223 then go with the bottom loading Haan block or similar. It will retain the bolt hold open feature. Save yourself a headache and get GOOD mags. I hear a lot of griping about C-Products and Promag. So research that carefully. Top loading blocks are easier with a "dedicated" 9mm lower but if you want to use the bolt hold open on the Haan block, you need to remove the bolt hold open to put the top loading block in and out.

You will need a buffer for the 9mm as well. The carbine spring is fine, but you'll need a heavy buffer and it should be a bit longer to limit the travel for the shorter 9mm round.

When you add up all the costs for building a "convertable 9mm" upper and parts, you may find that you want to make a dedicated 9mm.

I chose to do make this one, instead of conversion pieces all over the place. The cost ended up being just slightly higher than buying the block, mags, and upper. Since I have all the Glock 33 rounders, it just made sense. It is built on a Glock Fed lower from Lone Wolf Distributors. No mag block needed.

picture.php
 
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tulsamal

New member
I just started down the LW road myself.

But not in 9mm.

As I said, just started. When it is up and running, I'll have a full review and pics!

Gregg
 
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BODAME

New member
Pistol Caliber ARs

Mine is a AR45
Olympic Arms 45ACP with Red Dot
Timberwolf Lower (Dedicated)
Uzi Mags with Block to fit 223 Magwell
Made it for IDPA Mult-Gun Pistol Caliber Division

Down Side:
Mags are Scarce and Expensive
Bolt does not Lock Back when Mag. is empty.

There are other avenues, but this one made the most sense for me with Parts I had on hand.

Very Accurate
 
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SundownRider

New member
I see Olympic Arms is now producing mags for their pistol uppers that do not require magwell blocks.
That moves the ball in Oympic Arms court.

Next question: Would those mags work in a CMMG or RRA upper?

The reason I ask is there is about a $100 difference between the uppers.
 
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rjrivero

New member
SundownRider said:
Next question: Would those mags work in a CMMG or RRA upper?
Click to expand...

Olympic is a proprietary upper. They use a barrel and bolt that is unlike any other in use right now.

Can the Colt/Rock River style upper fit? I'm pretty sure it can, with the right machining of the bolt. (Similar to what I did for my Lone Wolf setup.)

But, I've not done it, nor have I seen one done that way, so I can't say for sure.

I will make you an offer though. If you want to get a magazine, and have it sent to me, I'll be happy to try it on my Modified Rock River Arms upper with one of my standard lowers to see if it will run.

I will then send you back the magazine. With a full report. I may be able to get some video if you really want it.

PM me if you're interested.

RJ
 
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BODAME

New member
Pistol Caliber ARs

Quote "Next question: Would those mags work in a CMMG or RRA upper?"

First: Do you mean CMMG or RRA Lower ?

Second: My understanding is the Olympic Mags were designed for their Uppers, and as previously stated the 45ACP Bolt is different from a 223 Bolt.
 
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rjrivero

New member
BODAME said:
Quote "Next question: Would those mags work in a CMMG or RRA upper?"

First: Do you mean CMMG or RRA Lower ?

Second: My understanding is the Olympic Mags were designed for their Uppers, and as previously stated the 45ACP Bolt is different from a 223 Bolt.
Click to expand...

I'm pretty sure he means with the CMMG/RRA Upper. The "mis-match" is due to the fact that the CMMG/RRA/COLT 9mm bolt is designed to be used with the dual feed mags, where as the Olympic Arms is setup to use single feed mags.

Now, Olympic Arms is making magazines that have the ejector built in, and are longer front to back like a standard AR magazine. One would have to assume these are designed for the single feed bolt that Olympic is currently using on their proprietary uppers.

So, the question, if I read it correctly, is can this new style Olympic Magazine be used in a standard lower, with a Colt/CMMG/RRA upper.

I *believe* the answer to be "yes." But I would have to have the magazine in my gun with my modified RRA bolt to be positive.
 
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SundownRider

New member
Okay. I took the plunge and ordered an Oly .40 cal upper that comes with the larger style mags. I hope they will work with my CMMG lower. We'll see and I will be reporting in about two weeks.
 
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rjrivero

New member
SundownRider said:
Okay. I took the plunge and ordered an Oly .40 cal upper that comes with the larger style mags. I hope they will work with my CMMG lower. We'll see and I will be reporting in about two weeks.
Click to expand...
So you're going to make me order a magazine and test it for myself......Fine. ;)
 
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