Press with the highest mechanical advantage?

[Fire Dog]

Roller Handle?
You bet, I put one on my CoAx some years ago and that helped the strain on the wrist as the pull is now not requiring the wrist to roll rather it is a straight pull down.

Ergonomic style roller levers. – Inline Fabrication

Ergonomic roller lever arm inline fabrication hornady lee dillon lyman RCBS ergonomic reloading reload press aftermarket after market

inlinefabrication.com

 

[muleystalker]

As stated above Imperial case lube or ROYAL case lube and try a roller handle. The other thing that could make a world of difference and is overlooked by many is cleaning your sizing dies often! Use brake cleaner and an appropriate size bore mop or big cotton swab, you will be surprised what a difference that will make. People don't realize how dirty your dies can get and old case lube can gum them up real bad

 

[DDriller]

A Walnut Hill press is a beast if you really need a strong press.