Re: 300 RUM to 7MM RUM
to the best of my knowledge all you need to do is run it in your full length sizing die. Make sure the cases are lubed sufficeintly. I have never taken the 300 ultra down to 7mm ultra and would have tried it for you but I only have a Redding type S bushing die for the ultra. I have taken .308 down to .708 in one step without a problem. As far as neck thickness my Nosler 300 ultra case necks are .004 thinner than the 7mm ultra so there will not be a problem as far neck thickness. If you would like I could send you one of my Nosler 300 ultra cases and you could try it.
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