Well, this is only my own opinion & will probably get blasted for it from the "but... but my rifle is new and better than the old ones". And I am assuming you are talking a "toggle action" and not a single shot... if your using a single shot carry on with what your planning.
If it's a toggle action it is still an 1873 design with all the shortfalls of the originals. Although built with new, better steel, and it is stamped with all sorts of new proof test marks signifying it won't burst or explode in your hand, the toggle still absorbs the force if you over extend the design engineering.
I own 4 or 5 toggle guns myself, I don't over- stress them and have never had a problem with any of them, however I have had several in my shop that have been severly damaged at the rear pin area by stout loads that wouldn't be a problem in ant other action. A couple have been relegated to "boat anchor" status. Problems with others include broken toggles, broken/bent rear pins, deformed rear pin holes. In the two boat anchor guns the frame stretched enough that the headspace was a measured 45 & 48 thou.
Know doubt there will be some hollering that they shoot magnum elephant loads in their toggle guns all the time. they are right as some guns come out of the factory with tight enough tolerances at the rear toggle boss in the frame that the gun works very well beyond its original design parameters, if you have one of these guns, consider yourself lucky & good to go. Most, however, don't realize they have high pin boss gaps until it's too late.
Personally, the 325 gr bullet wouldn't worry me...as long as the velocity was kept to original b/p loads (1300 fps in my books) for that caliber. My experience won't allow me to hotrod any toggle gun.