Or go to Chuck Hawks web site and look it up. ('specially ifn ya don't have the info for the calculator) Now the numbers on Chuck's are what he got with the gun he was shooting, so you have to take that into account. That ti-357 was unpleasent because of the almost non-existant weight of the firearm, so like PaulS said the momentum of the weapon will be large, so your arm has to absorb it.
Helicopter Bill