Please help me in solving a mystery for me.  I have searched the internet high and low to find out what the real differences are between these two guns.  I want to purchase one of them but cannot decide which one.  During my internet searches the only thing that I can find different between these two guns are as follows:

1. MK23 is a much larger gun.
2. Manual hammer release lever on the MK23.
3. Some kind of hexagon barrel.(I am not sure if this is in the USP but I do know that it is in the MK23)

That’s it.  That is all I got.  Now there has to be more to the MK23 than what I have mentioned above.  I say this because the MK23 is physically larger than the USP and cost double.  So what am I missing?  Is it double the cost simple because the gun is labeled MK23?  Does the MK23 actually perform any better then the USP Tactical?  

check out mark23.com or hkpro.com.  I have a tac and love it.  I hope this helps you.

My choice is the Tac. See my post in your other thread.