I wouldn't say less. It depends on what level 45 loads you are shooting. There seem to be about 3 different load levels to suit old and imported guns...S&W and Taurus.... and Ruger, Thompson, Freedom Arms. Standard factory fodder is loaded to low pressure as is the new cowboy action stuff, to account for the older guns and could probably be comparable to mid to upper level 357 loads. Custom loads such as Corbon are going to be considerably stiffer. No one can really get a good answer from Taurus on what their guns will handle. They just seem to spout SAMI specs which the factory loads are at, but it is somewhat of a consensus among shooters that they can handle more but may not hold up under the Ruger Thompson, FA level loads