Gas DI or Piston 9mm Upper ?

canmic

canmic

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I'm looking for a 9mm AR upper that is NOT blowback operated, either DI or Piston.

In a perfect world, it would work similarly to the Oly 9mm upper with the Hahn mag block on the lower and unmodified sten magazines.

Anyone know of anything like this?

Alternately, if I'm stuck with blowback, does anyone know of anywhere to get one of the Oly 9mm uppers in Canada?
 
No such thing. Ever heard of a DI or Piston Handgun? Me either, your stuck with blowback. There's Colt, RRA, PSA, piece together your own.

I don't even think Olympic arms is even still around and why un modded sten mags? When there's legal 10rd mags.
 
OkayShooter said:
No such thing. Ever heard of a DI or Piston Handgun? Me either, your stuck with blowback. There's Colt, RRA, PSA, piece together your own.

I don't even think Olympic arms is even still around and why un modded sten mags? When there's legal 10rd mags.
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Desert Eagle.

Never heard of a piston 9mm AR though

Op, don't worry about it being blowback, mine is accurate and can run a lot of rounds through it between cleaning without any issues.
 
I believe there is one manufacturer (Troy, maybe??) coming out with a gas DI 9mm AR, it was mentioned in a thread here a couple of months ago. If it is Troy, hopefully Gadget will chime in.
 
OkayShooter said:
No such thing. Ever heard of a DI or Piston Handgun? Me either, your stuck with blowback. There's Colt, RRA, PSA, piece together your own.

I don't even think Olympic arms is even still around and why un modded sten mags? When there's legal 10rd mags.
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I meant un-modded to fit, of course they are pinned and legal.

And there are several examples out there of DI and Piston 9mm uppers, I just can't find any sources in Canada. I found a few different ones in the USA.

olympic arms is around at www.olyarms.com
 
cr5 said:
Desert Eagle.

Never heard of a piston 9mm AR though

Op, don't worry about it being blowback, mine is accurate and can run a lot of rounds through it between cleaning without any issues.
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The main issue with blowback vs DI or piston is the beating the lower takes. I have been reading about cracked lowers and egged out pin holes on lowers caused by blowback uppers
 
canmic said:
I meant un-modded to fit, of course they are pinned and legal.

And there are several examples out there of DI and Piston 9mm uppers, I just can't find any sources in Canada. I found a few different ones in the USA.

olympic arms is around at www.olyarms.com
Click to expand...

I mean like why do you want to use sten mag? They're more $$ harder to find. Limit to 5 rds. When cheaper more common 10 round mags. Well I haven't seen oly arms up here much. Few random here and there.
 
I have about 2 dozen old sten mags from back when they were going for $5 each. I pinned them years ago after they announced the mag cap rules before they took effect.

It's easy to get a 9mm glock magazine block for an AR lower for all the different uppers out there, but only some uppers will work with the sten block, has to have the extractor a bit different (like the Oly not like the colt)
 
I don't know who makes 9mm DI uppers commercially, but a bunch of guys on CNC Guns made their own DI 9mm and 45 uppers.

The DI uppers shoot soooooo much softer than the blowback ones
 
If you go with the MGI hydra it is totally up to you how you want to set up your 9mm barrel - blowback, DI or piston. In fact you can have 3 different barrels and switch them out in seconds if you wanted. ;)
 
canmic said:
I have about 2 dozen old sten mags from back when they were going for $5 each. I pinned them years ago after they announced the mag cap rules before they took effect.

It's easy to get a 9mm glock magazine block for an AR lower for all the different uppers out there, but only some uppers will work with the sten block, has to have the extractor a bit different (like the Oly not like the colt)
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Mag block I had used colt mags, but I had promags, uzi mags etc. But I was able to remove it to multi purpose that lower to 223/556. I just ran a M16 hammer a 9mm buffer. It inserted like a mag and than I tightened a allen hey that pushed little tabs out locking it into the receiver.
 
I have an Oly Arms 9mm conversion that runs Sten mags. And I tried to do what you are looking for. I could get the action to cycle DI but ran into a huge problem feeding from the Sten mags through the barrel extension. The gap between the Sten mag and the chamber is just too long and the steep feed angle causes serious issues.

I never tried the Colt pattern mag/block combination but that sets the mag further back and includes a feed ramp that I think allows the rounds to feed straighter at less of an angle through the barrel extension.
 
Suputin said:
I have an Oly Arms 9mm conversion that runs Sten mags. And I tried to do what you are looking for. I could get the action to cycle DI but ran into a huge problem feeding from the Sten mags through the barrel extension. The gap between the Sten mag and the chamber is just too long and the steep feed angle causes serious issues.

I never tried the Colt pattern mag/block combination but that sets the mag further back and includes a feed ramp that I think allows the rounds to feed straighter at less of an angle through the barrel extension.
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So the oly worked well in blowback but then didn't feed well when you converted to DI? Do you think that putting in a feed ramp would be possible and help the problem?

Which mag block did you use? Or were you using the modified sten mags oly sells with the extra part welded on top to fit the regular mag well?
 
The Oly upper uses a special ejector so you couldn't use it for a DI gun. I built another upper and used the Sten mag block. That didn't work.

How would you add a fed ramp to an OEM AR upper? The Colt system has a feed ramp built into the mag block.

FWIW the Oly system requires a small mod to be made to the Sten mags to get them to work reliably. They need a screw added to the spine to properly engage the mag block.
 
The Tavor does have a softer feel than the Colt even if both are blow back operated ....

1-IMG_0242_zpszmee6gpx.jpg
 
canmic said:
The main issue with blowback vs DI or piston is the beating the lower takes. I have been reading about cracked lowers and egged out pin holes on lowers caused by blowback uppers
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Strange, my 9mm AR started out as a Bushmaster Carbon-15 9mm (new slickside upper and a new barrel) and it's very soft shooting and feels like the lower would probably be under less stress than a 223 lower. That's just judging by felt recoil though, my 9mm is so gentle that I've let my 8 year old nephew and my 14 year old daughter shoot it and they both had a great time.
View attachment 49598
I'll probably be changing the stock and grip soon since I have a couple extra Magpul CTR's and Ergo grips kicking around.
That's an ALG Defense forend on there.
I really need to remember to take pics with a mag in it :)
 
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