If your going from the Speer manual, it list the CCI LRM primer for use with 748. However Winchester/Olin' s data lists Standard LR primers. Using CCI or Federal primers I recomend you use the magnum primers, for Winchester' s WLR primers work just fine using 748 or H380 in my 06 and .307. Honestly I' ve not noticed any appreciable differences between the LR magnums and the WLR' s, they tend to run a little hotter.