Sorry if this has been addressed before, i couldnt find anything in my searches. I'm wanting to know what makes the ATF give one product the label of a stock and another product not. I understand the if the design of the product is to be shouldered its a stock but is there anything else? I was wondering about taking a Magpul MOE stock and cutting off the pieces that come off the buffer tube to make a point, thus giving you the same check weld area of the thordsen tube and CAA combo but allows LOP to be adjustable. Would the fact that its still adjustable or that it was originally considered a stock still make it considered a stock?  I know its a touchy area to go dancing around ATF rules and Im not going to try anything unless I get a clear answer. Just a thought i had about solving the LOP problem I am facing.

Yes.
If you have an idea for a different type of product in mind, you need to design it to be different from the very beginning.
ATF will take one look at what you're talking about doing and charge you will possession of a SBR.

Even if you got approval for your cut down stock that's no longer a stock, you're tip toeing around a grey area by using a buffer tube made to accept a stock.
If you had that item and a useable stock in the same location it would also be constructive possession.

Thank you, thats what I figured but wanted to check anyway. I guess its back to the drawing board.

Your idea would still be classified a stock IMO. Because it was originally a stock, and your using it on a tube that can readily accept a stock.

What is a stock and not a stock is an arbitrary ruling by the ATF tech branch

The adjustable part will get you. I use the "stocks" like you have mentioned, except all of them are blind pinned and I use a high strength epoxy also once length of pull is established, looks like the thordsen with the caa on it but I am not going to say it is not a gray area.