In theory couldn't one load 7.62/39 subsonic and shoot it through a 7.62 ar upper?

............ you know your right ...........

DOH!!!!!!

Quoted: ............ you know your right ........... DOH!!!!!!

it sounds a lot more cost effective, possibly affordable for me  

Quoted: In theory couldn't one load 7.62/39 subsonic and shoot it through a 7.62 ar upper?

Sure, but there are some downsides.

(1) I don't think the 7.62 AR uppers are ultra-reliable to begin with, so putting in an underpowered load probably wouldn't cycle the gun without significant tweaking.  A .300 whisper (or .300 fireball or .300-221 upper) will probably cycle out of the box with subsonics.  

(2) Can you buy heavy (i.e. 220 gr, 240 gr) .311 bullets?  If you're going subsonic, you want the heaviest bullet possible.

(3) Where is the cost advantage?  In either case, it's a new upper.  .308 bullets are cheap.  The only issue is the brass, and I know it can be had for $0.10/case if you look around.

Quoted: (2) Can you buy heavy (i.e. 220 gr, 240 gr) .311 bullets?  If you're going subsonic, you want the heaviest bullet possible.

Engel Ballistic Research, 220 gr "Jackhammer" load in the 7.62x39, subsonic that WILL cycle the AR.  Pricey.  He used to advertise that they were coated with pork fat  

Real problem is, where are you going to get reliable 7.62x39 mags for the AR .... at a reasonable cost?  Unless you go with the MGI Modular Lower that takes AK mags, the mag problem will be the biggest challenge ...

See the other thread on .300 Whisper alternative, I am getting ready to prototype 7.62x25 Tok with 168 gr bullets, GAS OPERATED.  Standard mags, off the shelf brass, off the shelf bullets.  Just need to make sure it will indeed work, however, 10 gr H110 under the 240 SMK will cycle the 300 Whisper, and ironically the load for the Tok (seated out further than usual) with the 168 SMK is also 10 gr H110 .... in theory it should work ....

If you go with a can on your rifle you better get at least a 1/8 twist on 220 gr +, subsonic loads or you may end up whipping out your baffles. I like the 300 whisper. I use it for withen 100 yards feral pig gun. A 150 gr sp at 2000fps head shot drops them dead. Realoading is the key to a 300 Whisper.

Actually, I was thinking of this, too.

Magazines and bolt fragility are the big killers of 7.62x39 practicality.. Past that, the cartridge does have some good bits going for it in the AR platform. Namely, as it turns out, there aren't any true .311" barrels for the AR; they're all .308".

I'm looking really hard for a .300 Whisper or 7.62x39 bolt action rifle now. Hard to do on a college budget, though.

Quoted: See the other thread on .300 Whisper alternative, I am getting ready to prototype 7.62x25 Tok with 168 gr bullets, GAS OPERATED.  Standard mags, off the shelf brass, off the shelf bullets.  Just need to make sure it will indeed work, however, 10 gr H110 under the 240 SMK will cycle the 300 Whisper, and ironically the load for the Tok (seated out further than usual) with the 168 SMK is also 10 gr H110 .... in theory it should work ....

Ooooooooh.  That sounds interesting.  Too bad my next purchase needs to be an Elk gun.  

CZ makes a 7.62x39 bolt action. i believe the model # is  "527 carbine".  they usually run just a little under $500.

Marty-

Any progress on the Tokarev?
I know you have the blank.
If it works good, I want you to send it to me to play with for a couple months...
I have not been "fun shooting" in months.
Test firing whispers and SPC's gets boring after a while.
I think this weekend has 10 barrel test firings lined up...
I need that CQB upper :)

Randall

Reliable, high capacity 7.62x39 AR

you forgot to mention...

www.ar47.com

... for those that do not know where to get one like that.

Randall

I thought about that after I posted...thanks for doing the work

Quoted: Marty- Any progress on the Tokarev? I know you have the blank. If it works good, I want you to send it to me to play with for a couple months... I have not been "fun shooting" in months. Test firing whispers and SPC's gets boring after a while. I think this weekend has 10 barrel test firings lined up... I need that CQB upper :) Randall

Working on the Tok ... borrow it for a coupla months???
Try test firing 25 .458 SOCOM uppers .... during lunch .....
QCB still sitting here with your name on it ....