Originally Posted by Mitchja95

Gentlemen: New to the forum. Need help. I've been reloading now for about a dozen years for my hunting rifles in .243 ,.308, 7 mm Remington mag., 7-08. Etc. I recently acquired a new-to-me Ruger M77 Mk II .338 Win. mag. I took it out yesterday for the first time to test some loads and my shoulder. For years I've loaded nostler BTs because I've liked the accuracy and performance on whitetail and muleys. I hunt the grasslands in western Nebraska. For this rifle I'm starting with 215 gr. Sierra Gamekings with Re 19. My initial impression is that we're going to get along fine.
Here's my dilemma: I've never shot a magnum rifle like this before. I wanted to know what the recoil would do to the cartridges in the magazine. I measured each cartridge with calipers and wrote on each one it's COL. I loaded the magazine, it holds three cartridges ,and fired a round. I could not detect any movement of the bullets in the case necks even though, of course, these bullets are not crimped. The tips of the bottom two bullets were flattened by the front of the magazine. The tip on the top bullet was Knocked out of round by the feeding ramp. Yikes!
I'm confident that when I am done tweaking this rifle I'll be shooting a sub MOA. IF I FEED THEM ONE AT A TIME! But what about when I'm in the field with a full magazine. What can I expect from my second and third shots?
Please help. Thank you