Barnes lists BC of the 338/160 TTSX at .342. The 257/100gr NosPart lists at .377.
Not much difference.
The beloved "Bob", (gotta hate that term--love the ctg) launches that 100gr at about the same as original posters 338Fed/160TTSX load.
Could drop, wind drift, SD and BC negate the 338 load to the same uselessness as the 257 load? Just say NO!