Ruger M77 in 7x57

Ruger M77 7x57mm

Q:  Recently I bought an old Ruger M77 MK I with tang safety at a  gun show. It is chambered for the 7mm Mauser cartridge and the  bore appears to be in good shape. However, I struck some serious  accuracy problems when I started reloading for this rifle,  particularly with light bullets from 120 to 140 grains. The guy  at my local gunshop told me that the 7×57 isn’t very accurate  with light bullets. As I don’t intend to load anything heavier  than 140gn spitzers, is there anything I can do to improve  accuracy?
Walter Harrison

A:  When  introduced,  the 7×57 was loaded with a very long 175gn  round-nose bullet. This required a very long throat ahead of the  chamber to accommodate the long projectile. Sporting ammo was  likewise loaded with a long bullet of 175 grains and most  European ammo contimues to be loaded that way even today. Because  of this factory 7×57 rifles have the same long throat today.   Because lighter bullets are shorter, they must travel through the  throat for up to 7mm before engaging the rifling. Because of the  high velocity the bullet gains before contacting the rifling, the  bullet often becomes deformed ever so slightly – enough to ruin  accuracy. However, I reviewed one of those early Ruger M77s in  7×57 and  found it was nowhere near as well made as later models.
The barrel had a .2856″ groove diameter, the chamber was oversize  and the throat was long enough to be truly called “freebore”   even with 175gn bullets. I found I could use hellacious powder  charges without getting anywhere near what could be had with a  better made rifle. Seating bullets farther out in the case neck  will help reduce the freebore area that the bullet must cross  before engaging the rifling. This way the bullet sustains less  damage and accuracy may improve. By the way, the 7×57 is a fine  cartridge. It’s well balanced and powerful, yet has light recoil  and is generally accurate. It was a favourite calibre with Jack  O’Connor and Prince Abdorreza Pahlavi of Iran who use it  successfully on game up to wapiti. He used Canadian  Dominion  brand ammo loaded with a 140gn bullet exclusively and said that  heavier bullets weren’t near as good killers. Personally, based  on power and performance a good 150gn bullet should be the  heaviest one should use in the 7×57. Good luck with that old  Ruger.




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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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