pin shear stress

Hello,

I am trying to find the stress on a pin caused by a reaction force.  The pin holds a jaw arm for a gear/bearing puller.  I've attached pictures of what the Jaw arm + pin would look like, and also just the pin itself with fixtures and a load applied.  Before I ran the simulation I did a simple shear calculation on the pin:

shear = V/A = 4V/pi*d^2

'V' in this case is going to be a load of 10/3 Tons, so about 6667 lbf.  The diameter of the pin is 0.375 in.  The shear stress is about 60,000 psi using that calculation.

So I set up the pin as shown, figuring the jaw arm only contacts a portion of that surface causing the reaction.  Once I get done with the simulation I get a max shear stress of over 100,000 psi as shown.  Am I missing something here?  Maybe I oversimplified my hand calculation, I'm not sure...

SolidworksSimulation