Hello,

I am new to pistol reloading. I am interested in loading some .500 WE plinking loads using Sierra 400 Gr JSP bullets. Can I used the Freedom Arms load data using Trail Boss powder designed for 400 grain lead bullets on 400 grain JSP bullets?

Yes, but check the overall length of the 400 Sierra in your gun before you load a bunch. I think I recall that the cannelure on that bullet makes for a long OAL, but I may be incorrect. I only tested a few three years ago, then settled on other bullets.

It's not the best policy to substitute jacketed bullets for hard cast bullets of the same weight. Pressure will be higher. How much higher? Dunno.

There is no pressure problem associated with substituting hard cast bullets for jacketed bullets of the same weight, though.

To confirm what you want to do, you might check Hodgdon's web site for ALL loads for .500 WE. Freedom Arms' data is an abridged version of these data. You may find [other] jacketed 400-grain bullet loading data.

But, as kenoneill wrote, be sure to measure crimp-to-nose distance of your bullet. FA puts a limit of .395-inch on this.

You might get better results using a faster powder (from the load data) with a near minimum load to get your plinking load.