I bought one of these pre-ban about ten years ago thinking that this would be one of the guns that would absolutely be banned and never made again.  I have shot about 100 rounds through this thing and it is about the worst handling block of sheet metal you can imagine.  I have been offerred 500 bux for it but don't really want to give it up.  
I thought about making a carbine rifle out of it as long as I don't have to drill holes through the thing to make a stock fit.  Does anybody know if someone makes a carbine conversion for these things or should I just stick it back in the gun safe for 10 more years?

There's a couple places that sell carbine uppers for them...isn't there a sling mount point or some such thing at the rear bottom of the reciever? That's where a stock would mount.

I had a pre-ban CM11 (carbine; detachable stock and 16" barrel"). It was...well, ok; you knew it'd work; it was too simple for it to NOT work. After it started double- and triple-tapping reliably, I got rid of it instead of bothering to work on it. (Yes, I told the person I sold it to that it does it. He didn't care, I guess.)

I wouldn't mind having a Class-III version of one, but that's impossible where I live. It'd never be more than a curiosity, either way...not something I'd bet the farm on if I had to. I have my HK94 for that

Ummm, market value for that is like $350-$400... sell it for $500 and buy the post ban carbine for $225 if you want a carbine version...  Spend the extra money on more mags and ammo and have fun.

Let it sit for 10 more years.  It's a great conversation piece, however as you already know it sucks.

Sell it for 500 and buy more ammo or another rifle.  Thats what I did.

Max

I also had a pair of Pre-ban M11/9 Cobrays.
One for each hand...
I bought vented scary looking bbl extensions for them both. Sold the pair to a friend of a friend for $1,000 back in 96'. Bought a Para-Ord P-10 with the $. I still haven't figured out which was the bigger POS....

The Class III version is the cats ass.
I just sent mine off for the sten mag conversion. I agree, a semi version would be a bummer. Is it closed or open bolt? Open bolts carry a higher price. If it was me I would take the $500.00 and run.

Bob

If you get the screw on muzzle attachment with the nomex sleeve you can safely bump fire a semi...  or so I'm told...

My only Class III is a 11/nine, and its been sitting at my buddy/dealer's house in Idaho for the past nine months. Only thing that would make it better is a .22lr conversion.

Had a semi, thinking of one again. Talk about the simple way to make a gun, and (hushes) easy to convert to its original tendancies. The M11/9 is the modern heir to the STEN.

Been thinking about a .45 cal version that takes grease gun mags. Someone makes a very nice example with Weaver rail and a side-cocker.

Original tendencies?  Sorry, that's an E ticket that I couldn;t afford to pay for... Full auto would be fun, but certain modifications will land you in federal prison for an extended stay...  No thanks.  Move to a state where class 3 is legal and you can get a full auto Mac for around $1,500 and no worries...