I've been screwing around with trying to change a bunch of Bushmaster fixed telestocks into working telestocks. Here's what I've come accross. You have to punch out two roll pins that run through the stock and into the buffer tube. After that you have to unscrew the allen head bolt that goes through the latch. Once you do that, you can slide the old stock off the old buffer tube.

At this point you will be left the the following usable parts. The stock, the receiver (end) plate, the telestock lock (castle) nut and the telestock stock latch. New parts you will need to do the swap will be:

Telestock slide locking pin
Telestock lock pin spring
Telestock lockpin nut
Telestock lock pin roll pin
Car buffer tube
Car buffer spring
Car buffer

Thats not all... you have to drill a hole in the top of the telestock and down into the stock where the locking pin goes down to the bottob of the stock. But not all the way through. I havent actually tried it yet so I dont know what size drill bit you need or how far you have to drill. But I plan to try and get a bit that fits down the hole of a regular telestock, and see how far it goes down before it stops.

Once you drill the hole in the top of the stock and open up the existing hole a little so the lock pin will go down far enough, you should be able to put it all together. Im not 100% sure, but I think it will fit on a standard CAR buffer tube. Like I said, havent tried it yet so I dont know.

In my opinion, if you have just one stock, I'd just get a new stock. Its more work than its really worth and the money you will spend in the parts and shipping, it seems more work than its worth. If you have multiple stocks to do it may just be worth it?