I bought a barrel off a new Mark 2 but I want to have it shortened to 17" , ensure headspace is perfect and get the barrel threaded as well.

I already pressed my old barrel out of my receiver. The small cross pin came out much easier than I would have expected, all I needed was a small punch.

I have a 12 ton press from AK building and it made short work of these barrels. It was indeed very very tight and it did POP like you find on AK barrels. If anybody has worked on Bulgarian kits or rusted Romanian kits you will know how jammed stuck they seem. I would definitely invest in some sort of penetrating oil and let it soak in there for at least an hour.

If you do not have access to a press you could always get a brass rod or wood dowel (1/2" diameter) and punch the barrel out. It would take you forever but it would work. The brass rod may hose your chamber but if you are dumping that barrel anyways who cares.

I am having this place do my work to this barrel.
http://www.aquilafirearms.com/

Give Chris a call. He actually answers the phone when you call and if he is working on something at that moment he does call you right back. You cannot get more straight up than that. Just give him a call and he'll make it happen.