Hello to everyone this morning.  I am new to this board but have enjoyed it a great deal.
If I installed a non-pinned telescopic stock
(Functional) on my ar-15 how to I do this legally to comply with BATF guidelines.

Also I would like to construct a semi-auto version of a Colt Commando.  Again how do I comply with BATF guidelines to insure the legality of both firearms.  The Commando would have a 11.5" barrel and fuctional telescopic stock, however the action would be semi-auto only.  

Any advice would be appreciatd.  I live in the state of Louisiana if that is of any benefit.

Short version of the answer is that the telescoping stock will need to be on a lower receiver that was lawfully possessed as a completely assembeled semiautomatic assault weapon on 9/13/94 (date of the 94 cime bill).

The 11.5 barrel will need to be registered as a short barreled rifle (SBR) which requires a tax stamp and seperate forms to be filed and wait for approval.

I'm sure others can give a more complete answer but this will give you some info to start on (try the search function) while you wait for the other answers.

Oh god, not this question again!

Just drill it and pin it and have fun!

Actually the ATF will love you more if you weld the CAR stock in the open position and just put on a 16in barrrel [:)]

The other choice is to remove the gas tube assembley so its not semi-auto anymore ([url]http://www.quarterbore.com/nfa/sbr-aow-pistol.html[/url]).

It would probably easier and cheaper just to buy a pre-ban rifle and reconfigure it though.

What about welding or pinning it in a partially open position, say about halfway?

The definition of semiautomatic assault rifle 921(a)(30)(B) doesn't say anything about the length of the stock itself, just says "a folding or telescoping stock".