I can't see any useful reason to go that light with a 338 RUM. A 338 Federal, sure.
But a 225 gr or heavier will have higher BC and MUCH higher momentum than a 30 cal class bullet, and can take advantage of the terrific case capacity of 338 RUM
Inside 300 yards, pretty much all modern cartridges are flat-shooting. Past 300 yards, heavier 338 RUM will give much better terminal performance than a 185 because a 185 is going to give up velocity in a hurry relative to 225 or 250. Barnes TTSX 250 has a BC of over .60. Guarantee you it's faster at 300+ than a 185.
I concur with sgt-zim, I don’t see a need to go that light. A 225 gr Barnes TTSX has a b.c. of .514 and can be started out north of 3000 fps and a 250 gr Barnes LRX has a b.c. of .602 and can start out at 2900+ fps.
I’ve settled on those two bullets and the 225 gr Swift in my .338 RUM. The Swift worked great in Namibia last year.
Mule deer and Colorado elk seasons almost done! Hunters driving farm roads, looking for racks, their PH driving them along, I ask that you not pull into my drive. The buck behind me, on the boundary line of the GMU somehow knows. The hunter laughs, I would invite you in to see my Searcy rifles but social distancing prevails, darkness arrives and the buck slides away into secret tree grove...