7mm Remington Magnum

Major differences in 7mm barrels and brass


Q: I tried the load you gave me for my 7mm Remington Magnum and it only gave a muzzle velocity of 2860fps, rather than the 3025fps you quoted. I had to increase the charge by 2gn to get 3000fps. Why do you think this happened?

– Trevor George

A: When reloading the 7mm Remington Magnum it pays to stick with the components listed in your manual, if possible.

From past experience I know that case capacity in different brands of brass can vary by up to 10 grains.

I used Norma brass in my old Mauser with 24″ barrel and my two best loads were: Nosler 140gn Partition and 70gn of H4831 for 3284fps; and the 160gn Nosler bullet and 68gn of Norma 205 for 3110fps. The latter was an excellent load.

But then there’s the difference in bore diameters. For your information, some of the barrels I checked in past years varied quite a bit: Remington 700, .2834″; Schultz & Larsen, .2839″; Browning BAR, .2839″; Ruger M77, .2852″; and the Shilen barrel in my custom Mauser, .2844″.

Les Bowman told me he once had five new factory rifles on the shelf at once, all with 24″ barrels, and in the five rifles he found a difference of 250fps with the same loads!

No wonder the data in loading manuals varies so much.

 

 

 


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Nick Harvey

The late Nick Harvey (1931-2024) was one of the world's most experienced and knowledgeable gun writers, a true legend of the business. He wrote about firearms and hunting for about 70 years, published many books and uncounted articles, and travelled the world to hunt and shoot. His reloading manuals are highly sought after, and his knowledge of the subject was unmatched. He was Sporting Shooter's Technical Editor for almost 50 years. His work lives on here as part of his legacy to us all.

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