The Ruger 77 is also available in the classic 7x57mm Mauser if you can find a used one. My brother had a 6.5x55mm Swede which I shot, so I am familiar with the cartridge. The fact remains that if you are a handloader, the 7mm Mauser is the more versatile cartridge that can take larger animals down quicker, and it does so with a very minimal increase in recoil. Both rifles are available with very fast twist rates, which allows the use of long, heavy, soft bullets. Across a wide range of game weight, game toughness, and distance, that kind of bullet launced at moderate velocity will outperform the much faster magnums with slower twist firing a tougher but lighter bullet. The 162 grain A-Max in a 7x57mm Mauser is something I learned from a New Zealander. BC of .625 means it is traveling fast enough at 500 yards to give reliable expansion without hitting any bones. A local here with a 6.5 Swede that used Berger bullets had nothing but failure several times. My 7x57mm CZ 550 has had nothing but outstanding results with the Hornady 162 A-Max. I blew a Mule Deer Buck spine completely in half at 200 yards (instant knockdown) and the recovered bullet had 38% weight retention. At 150 yards, a Mule Deer Buck shot broadside just behind the shoulders had his lungs turned into oatmeal that poured out when field dressed and a decent sized exit wound. The 162 A-Max has been working more like a Nosler Partition for me as far as terminal ballistics, but it has the accuracy and retained energy of a long range match bullet. Without bonding of the core and the associated price tag. At under $30 per 100, and at a longer range of reliable expansion than an Interbond and Accubond, unless you are breaking Elk shoulders or something like that, it is THE go-to bullet for long range hunting in 7x57mm. I don't believe the A-Max in 6.5mm has quite the same reputation. People with slow twist 7mm rifles cannot use it and there is no A-Max in 7mm that is lighter as an alternative. The 162 A-Max is a 7mm Mauser handloader insider secret and once you use it you realize you have hit the jackpot with a combination that cannot have its performance explained by reading charts and must see performance on game with your own eyes. It is not available anywhere from any factory in the "above lawyer load" that I use and so it is strictly for those with fast twist rifles. Any loading that is weak enough for old Mauser 95 rifles will not launch it fast enough for truly long range work, but would work well at close to medium range. You MIGHT get similar performance in 6.5mm with proper handloads. If I had a 6.5mm Swede, I would try it. However, commercial rifles often have a slower twist than the original 6.5mm Swede. My MODERN and STRONG 7x57mm Mauser has the original fast twist with long leade for long and heavy for caliber bullets. It does not really like the 140 grain and lighter bullets. If you shove the 162 A-Max into the case far enough to magazine feed in an intermediate length receiver, you would cut case capacity and possibly be far below jam length. Most of my 7x57mm loads are compressed loads, and I have a .270 Win length magazine box that lets me seat long bullets out as far as I need to. My receiver was made to handle 65,000 PSI Win 270 ammo, so even hot Norma ammo at around 55,000 PSI places no undue strain on the rifle. Norma ammo is around 2750 fps with a 150 grain bullet, far above anything you will see factory loaded in the USA. A modern 7x57mm loaded to its true potential will about equal the original .30-06 loads for energy, and that's considered enough to hunt just about anything in North America.
