I just purchased a collapsible stock. Can someone tell me the proper procedure of removal of the original stock? Must the buffer tube be removed? If so, how can this be done? Special tool? Thanks

Yes. You will need to replace the buffer tube. I'm sure there's already a thread about it. Search for it and you'll undoubtedly find it, or, someone who has the link will be along any second.

Quoted: Must the buffer tube be removed? If so, how can this be done?

Unscrew it.

I'm not sure of how to remove the origianal buffer tube. Certain tool? Can someone give me a step-by-step removal of original stock and assembly of collapsible one

Separate the upper and lower.

Remove the buffer and spring from the tube.

Remove the screw in the back of the buttstock with a Screwdriver.

Slide off the buttstock assembly. (watch for the spring and detent for the rear push pin)

Unscrew the buffer tube from the receiver. (watch for the buffer detent and spring)

You may need a bench vice if the buffer tube has been appoxied or loctited in place.

Quoted: I'm not sure of how to remove the origianal buffer tube. Certain tool? Can someone give me a step-by-step removal of original stock and assembly of collapsible one

See that button above labeled INFORMATION ? Click it

Now scroll down to Manuals/Downloads - Click it.

Now scroll down to Unit and Direct Support Maintenance TM 9-1005-319-23&P
Click it - download it  - then read it.  Chapter 3 will contain step-by step directions (with pictures & tool list) of how to remove the RECEIVER EXTENSION and replace it with a TELESTOCK RECEIVER EXTENSION.  You will not find the words 'Buffer Tube' in the manual.

Removal Of Rifle Buttstock

1. Remove the top buttstock screw.

2. Remove the buttstock, takedown pin's spring and detent, and the receiver extension spacer (A1 will not have spacer.)

3. Cock the hammer, depress the buffer retainer, and pull the buffer and its spring forward out of the receiver extension.

4. Remove receiver extension (buffer tube) with a wrench, while holding the buffer retainer in place.

5. Remove buffer retainer and spring.

Installation Of Carbine Buttstock

1. Install the rear takedown pin's detent and spring into their hole in the lower receiver.

2. Thread the receiver extension (buffer tube) into the lower receiver about 3/4 of the way.

3. Insert the buffer retainer and its spring into the lower receiver.

4. Tighten the receiver extension until it overlaps the buffer retainer to hold it in place.

5. Tighten the castle nut with a spanner wrench, while making sure that the takedown pin's spring gets compressed into its hole correctly by the back plate.

6. Slide the buttstock onto the receiver extension by pulling straight down on the latch.

7. Cock the hammer and slide the spring and buffer into the receiver extension while depressing the buffer retainer.

Thanks to all who replied. I have had no luck getting the original buffer tube off. Someone told me to heat it because they use loctite to install it at the factory I'm somewhat nervous about that. I dont want to heat the receiver and possibly warp it. I'm off to the gunsmith maybe he can help me. If I had known all the problems there would be getting this buffer tube off I would of left it alone and stuck with the original stock.

Quoted: Thanks to all who replied. I have had no luck getting the original buffer tube off. Someone told me to heat it because they use loctite to install it at the factory I'm somewhat nervous about that. I dont want to heat the receiver and possibly warp it. I'm off to the gunsmith maybe he can help me. If I had known all the problems there would be getting this buffer tube off I would of left it alone and stuck with the original stock.

You will not warp that receiver with a heat gun!If you suspect Loctite was used on the original tube, heat it up with the heat gun, put a open end wrench on the tube and remove it!

Quoted: ... I dont want to heat the receiver and possibly warp it. I'm ...

 Nobody's told you to put it in a blast furnace.  Heat the thing up with a heat gun or a propane torch around the receiver extenson.  You can't hurt it.