Bob, right hand cutaway cartridge below is the 350RemMag at 2.820" with a 300gr Barnes Original seated. There are no canelures on the Barnes Os I have. That bullet is out of print now. I have a small number of them but never actually loaded and fired one myself in the 350RM. But Con has elsewhere in this thread (bottom page two) reported using 310s with satisfaction from his Ruger77 in 350RM - 12" twist I believe. The 300 Barnes Os and the 310 Woodleighs are the same length.

L to R
35 Whelen - 310Woodleigh 3.280"
350WSM - 310Woodleigh 2.865"
358Win - 310Woodleigh 2.865"
350 Rem Mag - 300 Barnes Original 2.820"

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