9mm upper thoughts

[xjtwo]

I'm thinking hard about going with a 9mm upper for my next build, what are your thoughts?

Cheers,
J

[Colorado Osprey]

I went with the Olympic upper because you don't have to change any lower parts or need a dedicated lower. The Colt/RRA style needs a differrent buffer/spring and hammer to work correctly.

Colt actually prefers the Olympic style too and has on multiple occations tried to pay royalties to build the Olympic style instead of their own.

The down side to the Olypic style is the modified Sten mags or using unmodified Sten mags with a mag well adapter. Olympic also has new polymer pistol caliber mags but they are not listed on their web site... you need to call them directly.

If I had to do it all over I would buy the Olympic 9mm upper all over again. I'm just glad I only paid $499 back when AR parts were cheaper. The going price is now about $700.

[BadShot]

I have a dedicated RRA 9mm. It's persnickity about mags and has generated some of the most unique in the chamber jams I've ever seen. I completely attribute that to a very poor choice in mags :)

Out side of that, the dedicated rifle has some draw backs, but it is a training tool not just a plinker. Also works exceptionally well as an introduction to EBR's for new (generally female) shooters.

[Great-Kazoo]

i have a SBR Oly upper. sten mags are a 5-1 price point over either RRA modified uzi or Colt specific mags. The sten adapter is 1/2-3/4 the cost of the many different mags for the colt style. Sten mags function 95-100% of the time vs. the "many tweaks" possibly needed to get the colt/rra to run 100%.
you will see some "issue" related threads here regarding the colt/rra system. Over on ar15.com in their pistol caliber forums you'd spend a few days (ok many hours) reading all the "how do i get this to run right" post regarding the colt/rra's.
the colt system will cost more up front then the oly . your choice.

[xjtwo]

Thanks for the feed back...

Picked up a RRA flat top upper w/bcg has railed front block w/removable A2 front sight and has removable rear A2 sight, 9mm buffer, cproducts mag block, and 4 cproducts 32rd mags.
I don't have a 9mm hammer but read that you can modify the hammer so it runs and I read a bunch on ramped bolts....so I might look into that as weel.
I should get it all next week so hopefully the weather is good so I can take it out......then I'll know if anything needs tweaking or not.

Thanks again....
J

[Colorado Osprey]

Well.... Jtwo

How does the 9mm upper work??

[longhunter]

Thanks for the feed back...

Picked up a RRA flat top upper w/bcg has railed front block w/removable A2 front sight and has removable rear A2 sight, 9mm buffer, cproducts mag block, and 4 cproducts 32rd mags.
I don't have a 9mm hammer but read that you can modify the hammer so it runs and I read a bunch on ramped bolts....so I might look into that as weel.
I should get it all next week so hopefully the weather is good so I can take it out......then I'll know if anything needs tweaking or not.

Thanks again....
J

If you do not have a hammer yet I have an extra RRA 9mm hammer you can have it for what I have in it. $15.

[bluker1]

My 9mm upper is a RRA upper and a RRA ramped bolt. I am using the CProducts mags and the Hahn block and so far I have not had a problem with it.

I highly reccomend the Hahn block but the CProducts mags are a little spendy.

[80%Chimp]

I've got the RRA 10.5" upper with the RRA integral magwell lower. It has been flawless with C Products Grey Follower Mags. I tried the new red follower C Products mags & they jammed 3 rounds in 10. The gun was Jam-O-Matic during break in but that went away after a hundred rounds & lots of lubrication.
I'd get another RRA upper without hesitation. I used to have the Olympic Glock 9mm AR but that was a malfunctioning P.O.S. No amount of gunsmithing could make it function properly.

[michael_aos]

I've got the Olympic K9GL and it runs like a top.

I've also got an SBR lower. Was thinking about trying the RRA lower.

[longhunter]

I've got the Olympic K9GL and it runs like a top.

I've also got an SBR lower. Was thinking about trying the RRA lower.

Their deticated lower?

[michael_aos]

Their deticated lower?

Correct.