Why are the Reaction Forces different from the Mass Properties in the model?

I have simplified my issue with a very simple problem.

Part = a solid cylinder with A36 [default] defined [1731.767 lb]

Simulation

Material - same as part material

Force = Gravity - 386.22 in/s^2 [default]

Restraint = Fixed on Bottom face of cylinder

Mesh - very refined.

Reaction forces in y - direction = [1732.4 lb]

I know that the weight is not much different in this problem - but it is a hugh problem in my simulation analysis - I can give more details on my bigger issue - but first I need to know why these weights are different.