I am newer to loading rifle cases and for my 7mm Mauser cases I bought the traditional sizing die which ABSOLUTELY requires lube; however, for my .223 dies I bought the Lee Deluxe set with the Collet Neck Siding die.  Is specifically notes that no lube is required,  I've deprimed and sized about 100 rounds, and have had no problems; however, I'd like to get some expert opinions.  I've only completed about 10 rounds and as some of you may have seen I had some problems with the first rounds that I did (possible short-stroking), or gummed up chamber.  I'm working this out over the next weekend at the range.  I just want to know if you guys using Lee full length dies are lubing or not?  I appreciate your input

Lube 'em, no exceptions.

I would lube, the day you stick a case in a die you'll wish you had.  There is nothing more frustrating than trying to get a stuck case out of a die.  It will happen.

The only rifle die that I'm familiar with that does not require lube is the Lee collet neck sizing die.  All other full length dies require lube to my knowlege.  Carbide straight walled pistol dies do not require lube.

It is the neck collet sizing die.  Would you still lube?

No lube needed because you are only sizing the neck.

However...

You can only do this and use the brass in the same gun from which it was previously fired from (fire formed).

They most likely will not chamber in your gun if they were fired in a different one.

You need a full size die for this which you will need to lube.

No lube for the collet! Nooooooooooooooooooooo!

No lube on the CASE.  The die needs lubrication.  Clean and use an extreme pressure grease, just a bit, on the mating surfaces of the collet and body.

As a follow-up to everyone, I made an embarassing mistake:
I purchased pre-fired brass and used only the collet neck die.  I indicated earlier that I was having firing problems in my brand new AR with my reloads.  I am highly suspicious that my failure to do a full case resizing caused my issues as someone noted that the rounds would not chamber properly.  Last night I resized all of my .223 rounds that I did with the collect die with a full length sizing die and am hoping for better shooting results.  I now know that I have to keep track of which ammo that I shoot in my Mini-14 and that which is shot in my AR.  Beginners mistake

I Use a Lee Collet Neck Die in conjunction with a Redding Body die. Makes straighter ammo that way.