7x57 ballistics & brass

Bigunms

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Feb 7, 2012
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Is anyone here able to safely drive a 162 gr Amax to 2800 fps?

Which brass are you using?
 
According to Hodgdon data, it takes 284 Win or 280AI case capacity to safely reach 2800 fps from a 24" barrel. No way are you going to do that from a 7x57 case at safe pressures. If you go the AI route with a bit longer barrel and just the right powder, maybe. 2700 fps is achievable at modern pressures, though.

I would advise using Norma brass either way. Prvi Partizan might be worth a try, as well. I started out using Remington brass in my Ruger #1A. I am not happy with it.
 
I once had a 7x57 that pushed a Sierra 162 gr spitzer BT to 2495 ft/sec with 44 gr of IMR4350. That was a near max load in that gun. I do not recall barrel length, but it was a light sporter taper, so 22 or 24. Probably 22. The 7x57 has more case capacity than the 7-08, and should have at least 100 ft/sec advantage if the right powder is used in a modern rifle. I would like to hear from anyone loading for the 7x57.
 
Since my last post on this thread, I have more experience with the 7x57 and my understanding of the cartridge has changed quite a bit.

I was able to get some issues with the forearm on my Ruger #1A sorted out, which cleared the way for load development work. I have had very good results with RL22, though my rifle has been very finicky about what bullets it will shoot well. Both the 160 Nosler Partition and the Berger 168 Classic Hunter produce roughly 3/4" 3-shot groups @ 100 yards. Muzzle velocity is 2700 fps with either bullet, over the same powder charge.

My rifle flatly refused to shoot 162 AMAX bullets, no matter what I did. Ditto Berger 175 Elite Hunters, though RL26 was yielding outstanding velocities (2750+).

I am currently using Norma brass and have been very pleased with it. PRVI brass initially looked promising, but has turned out to be disappointingly inconsistent. RWS makes very good quality, tough brass. It is difficult and expensive to obtain, but could be worth it if intended for use with stout loads in a modern rifle.

When I use up my supply of RL22, I intend to switch to RL23. I have known RL22 to produce excellent velocity and accuracy. Based on load work in other cartridges, I expect RL23 will yield the same accuracy and velocity characteristics of RL22, with the added benefit of temp stability.

RL26 is also worth investigating for use in 7x57 with heavy bullets, but keep an eye on powder fouling. In more overbore cartridges, RL26 does not foul excessively. I have had problems with excessive fouling in smaller cases, using RL26. The fouling built up quickly enough to cause erratic results and pressure spikes after just a few shots. I did not encounter that issue during testing with 175's and RL26, but it is a characteristic to be mindful of during load development.

With current powders, I no longer believe that a muzzle velocity of 2800 is out of the question for 160 class bullets. My Ruger #1A, with a 22" barrel, easily launches 160's and 168's @ 2700, using decidedly unexotic RL22, at pressures that are still relatively mild. A 24" barrel and RL26, or some of the Vihtavuori powders, could easily put accurate loads @ 2800ish within reach for the 160's, and maybe even 175's or 180's, in a modern rifle. If I were planning to reach for that, I would probably go with RWS brass.

ETA: BTW, if I were planning a build, I would consider it a no-brainer to go with the AI version of the cartridge.
 
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