A press by any other name, is not a press, at least not in terms of the amount of weight a lifter can raise.

If you know anything about physics, its easy to understand that you can push press more than you can shoulder press, and you can push jerk more than you can push press. But right now, someone out there is saying, “huh?”.

With the push press, we add momentum recruited from the core, glutes and legs, generating upward momentum behind the load and allowing the smaller arms to complete the lift. Not only do we generate momentum, but we allow the elbows to open up, allowing more tensile strength (more engaged muscle fibre) in the muscle to move the weight to full extension. (Think about a HSPU. How many people have you seen drop three inches and return to pressed out, but as soon as they go four inches, they buckle like a cheap tent pole – tensile strength.)
Move on to the push jerk, and you add in a decreased distance of travel for the weight before you lock out your arms, as you re-bend the legs and hips then stand it up to full range using those bigger muscles. Now you have core and leg recruitment, further assisting the arms by asking them to do very little lifting at all, but mostly just opening up under the weight as you drop.
Interestingly, Greg Glassman says that the average person can Push Press thirty percent more weight than they can shoulder press, and they can Push Jerk thirty percent more weight than they can Push Press. Check this out next time you are working on a press sequence, if his assertion holds true for you, you will see something like the following:
   93# Shoulder Press
 120# Push Press
 153# Push Jerk
 130# Shoulder Press
 170# Push Press
 220# Push Jerk
Give it a try.