If you want a Lee shellholder, not that there is any special reason to use one with the Lee press.
You would be looking for Lee Shellholder NR 25.
https://www.brownells.com/UserDocs/Miscellaneous/Lee_Shellholders_Chart.pdf
You could also use RCBS,Hornady,Redding (both normal and comp.) nothing in the way of that. Some have cutouts for a eventual protruding primer or simply ease of access, some are tighter then others, some tends to be better finished etc.
plenty of products available-
And there is also plenty of presses out there that can be used for the 338 L.
Just make sure you have enough clearances for the round in the press without it becoming uncomfortable reloading.
And decide on the thread size of the dies or buy one of the ones with threaded inserts for standard dies as they leace a lot of options. Just be aware not all are 1 1/2 -12 some are 1 1/4 -12 too so know what you want before you buy.