Im beginning my AR15 mechanics career, and need to ask aquestion, or two.

I recently put a YHM FFtube on my Armalite M15A2. I borrowed a GI Armorers tool, and the barrel nut would nut budge, with any amount of torque. It kept shearing the teeth off the nut. I then tried to use my THM FF tube tool, and it sheared a few more teeth off, and then broke the teeth off of the tool. I finally had to dremel the delta ring off, and take a pipe wrench to the barrel nut.

I had no problems reinstalling the new nut, and the tube, after I fixed my YHM FF Tube wrench( I simply cut the shanks off of three drill bits I had, and press fit them in the wrench. It actually works better now, as the teeth are a lot longer).

To my question. Why was that damn thing so tight? Was I doing something wrong?

old, seized.

should have heated it or threw it in the freezer

I did heat it, thats what i didnt understand. Never thought of the freezer, dunno why.

use the air duster in a can - turn can upside down - spray out the liquid (which is incredibly cold so don't give yourself frost burn - way way colder than a fridge) - use enough to get your differential shrinkage and there ya go.  I use this technique on my wheel nuts that are torqued in too tight.  

oh yeah, don't smoke while doing this unless you wanna blow up.

Quoted: use the air duster in a can - turn can upside down - spray out the liquid (which is incredibly cold so don't give yourself frost burn - way way colder than a fridge) - use enough to get your differential shrinkage and there ya go.  I use this technique on my wheel nuts that are torqued in too tight.   oh yeah, don't smoke while doing this unless you wanna blow up.

Excellent idea. Quite a bit faster than the ol' icebox. I'll have to try that next time.