The barrel appears to be threaded, well not quite there appears to be a thread protector that is pinned on via the front sight so how do I get the pin out that is holding the thread protector on, and when I get it off what are the thread dimensions?

Try pushing the pin straight back, towards the rear of of the rifle.

The threads should be 14x1mm LH.

If your pin doesn't push in, take some pics so we can see what we're dealing with here. BSW

I tried pushing the pin back into the front sight and its not going anywhere I suck at posting my own pictures but this is a very similar picture on the net except it has the muzzle device attached

http://img159.imageshack.us/i/nhm3ld6.jpg/

It would be helpful to see exactly what yours looks like to know what is going on.

If your detent pin is protruding a bit from the FSB like in the picture you posted the link to then it is engaging a detent milled into the muzzle device to keep it from turning.  The pin is spring loaded and will push back into the FSB like shown in my picture below.  If your is protruding and stuck you might want to try a little penetrating oil and some light taps to free it up.  Once you get it pushed in the muzzle device will be free to turn.  Remember that the threads are left hand so it will unscrew clockwise.

I know it is a different rifle but my NHM-90 muzzle originally looked like this:



The detent pin was in the FSB but it was pushed all the way back by the "thread protector".  The thread protector was then tack welded to the FSB to keep it in place since threaded muzzles were prohibited by import restrictions.



A few minutes with a dremel cut-off wheel took care of mine.

well I got if off but by cutting the pin out. The pin was not spring loaded it could move back and forth but wouldn't move in far enough to get out of the way...so I pulled the pin out as far as it would go cut it off then pushed it back in. I also tried to remove the entire front sight tower but I couldn't get either of the pins to move with a punch pin and a hammer

Your pin may have been modified to lock the thread protector on in order to do away with the threads for import purposes.  Never heard of that before but it's possible I suppose.  The pins will come out left to right.  might try a little penetrating oil and let soak over night.  Even with the pins out the FSB sometimes still must be pressed off.  You can use a gear puller with a brass fitting to protect the muzzle.  To install a new detent pin you will have to remove one of the pins but not the entire FSB.

I have an early NHM-91 import.  The pin that held the muzzle nut on was not spring loaded, as a matter of fact it was just a long pin.  First remove the pin on the side of the front sight base (closest to the muzzle) with a pin punch.  Second, remove the pin that is in the center if the front of the front sight base.  Then remove the muzzle nut.  The muzzle nut on my rifle was not welded on.  I hope this helps.  Oh, the muzzle nut is threaded on with a left hand thread.

I have a feeling this is the answer. I'll try and pound that pin out in the next few days

That's exactly it.
I bought 3 NHM-91s around '93(?), two of them had a slotted full length pin secured by the front sight base pin, the other was exactly like a regular AK with the pin spring loaded.
The two "compliant" AKs had junk for barrels, one may have been bent, and the other had so much POI shift as well as "droop" on the bipod it was unuseable after a mag of ammo.
The third, with the proper spring loaded muzzle nut pin, has one of the finest AK barrels I have ever seen, no significant droop, POI shift, accurate, a terrific weapon. Needless to say, I kept it.

well i got the punch pin and tried to pound the pins out (left to right) and they wouldn't budge so what is the deal?

Try soaking them with penetrating oil for a day or two.  Then try again.  Patience and perseverance.  The pin should tap out with some resistance.  I would not remove the pin completely from the front sight base, but just enough to slide the detent pin out.  My detent pin was the hard one for me, then the muzzle nut did not want to cooperate.  Good luck.

You might try to get the pins out by going right to left  as our NHM 91 was like that.Mad Max son of Madtechcool

Used a dremel with a cut off wheel - easy as could be.  Then replaced with aYHM Phantom.  Very happy with result.

I got a tapco brake to replace the muzzle nut and the stupid thing wont fit! It screws on but after about three turns it gets very tight. I checked the threads and they don't have any burrs on them is it possible that my NHM-91's threads are off? or has anybody heard of tapco screwing up threads before?

My last 1 was right to left for sure.

I have bought a few muzzle nuts and slant breaks from a few sources that were threaded improperly (or were not the pitch i ordered). It is not uncommon. Try again with another and remember LH.

Did the muzzle nut screw on okay for a few turns and then lock up? If so, try another one. I have had to force some before at  about 1/2, but be careful. Better to try another nut or break than to damage the barrel threads. The threads could have been turned down and then rethreaded 1/2 x 28 RH (same as ARs). Look at the muzzle nut thread pitch and the barrel and see if they line up or not.  If 1/2 x 28 RH, try cncwarrior. They are great to deal with and have what you need.

Close up pictures of the barrel threads will help us tell what you have. What is the exact outer diameter of the barrel at the treads? Is it at or less than 0.5"?

mine was a small ring with 4 notches. The pin would sit in one of them. Previously I tried to press, and hammer it out. I just used a rotary tool on the pin 2 minutes ago. and screwed on a device that I had for years. I wish I knew how to show pictures. Thank you for showing me the link to this.

Just curious as I have an NHM-91 with the same solid pin setup, wouldn't removing it make it non-compliant with 922 unless you swapped out the rest of the needed parts with US made stuff?

yes.

went with US made stock, grip, hand guard, muzzle device, and 3 fire control parts - overkill!