Ledd Slinger
Silver $$ Contributor
Nice photo. Great visual comparison of all the popular big 30 cal magnums

I personally enjoy the 300 Norma Improved. When improved, it pushes the case capacity up to around 110gr H2O and still has the shortest case length of all the big 30's. Allows for better magazine feeding when seating big 215-230gr bullets to the lands and staying out of the donut area of the neck. Downside of course is that you are limited to actions with a Lapua bolt face.
Picture of a 28 Nosler case beside my 300 Norma Improved and water weight capacity measured on one of my scales. Peterson brass in 300 NMI capacity is 110.2gr. I have Lapua 300 Norma cases on hand, but have not fire-formed any of them yet to check the overall H2O capacity.

Empty fire-formed 300 Norma Improved Peterson brass case with fired primer installed. Primer filled with one small drop of water, case body empty. 311. 6gr

Same Peterson 300 Norma Improved case filled with water dead even with top of the neck. 421.8gr
Total H2O capacity: 110.2gr.

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