7x57 Mauser--Is anyone loading this cartridge to its potential?

[Calamity]

The 1892, 7x57 Mauser is, I believe, the parent pattern case for most of the rimless American cartridges, such as the .308, 30-06 and .270 Win. I'm talking about head dimensions. SAAMI lists max chamber pressure for the 7x57 at 50,000 CUP, and for the 7mm-08 at 60,000 CUP. The .280 Rem, 30-06, .270 Win all run about 60,000 CUP or higher. I understand that ammunition makers load the 7x57 at around 46,000 CUP because there are some old M95 small ring mausers still in use, that might not stand the higher pressures. Does anyone out there load the 7x57 to 60,000 psi in a modern rifle, and if so, what kind of ballistics do you get? The 7x57 has greater case capacity than the 7mm-08, so it should out perform the '08.

 

[benchracer]

Yes. I run both the 160 Nosler Partition and the 168 Berger Classic Hunter in my Ruger #1A with RL-22 @ 2700 fps. Same powder charge. Same velocity. Same POI. Same accuracy. According to QL, this is still a pretty mild load around 54k psi. With this combination, I cannot safely reach the next node.

The 7x57 has enough case capacity to utilize RL-26 with heavy bullets. I was able to push the Berger 175 EH's to 2800ish fps without issue. My #1A just refused to shoot them accurately. The additional case capacity of the 7x57 allows it to handle slower powders and heavy bullets better than the 7-08 can, provided you have the necessary free bore to take full advantage of the case capacity.

Because my 7x57 is not a long range rifle, and because it is very picky about which bullets it will shoot, it is set up for a max distance of about 400 yards. The Nosler and Berger bullets that it likes are easily adequate to that distance @ 2700 fps.

The doe in my profile pic fell to the 160 Partition at a range of about 100 yards. The season prior, I took a spike buck at just over 200 yards with the same load. I hope to one day hunt plains game in Africa with this combination.

 

[Calamity]

Thanks, benchracer. I am encouraged by your experience with the 175 wt @2800 fps. That is '06 performance. Purely from a "one best all around load" theory, I tend to favor the heaviest, highest BC bullet I can get in any caliber. I think that may have been Paul Mauser's philosophy, based on his rifles. I'm glad to see the bullet makers are producing heavier bullets in most calibers. Recent years' military sniper schools may have helped to kick-start interest in ballistics science and long range performance. Modern manufacturers use a middle of the road rifling twist in all 7mm's that favors the 139-160 grain wt range, a 1:9 twist. I think the original 7x57 spec called for a 1:8.6 twist for the 173 gr ball ammo. I guess that means a custom barrel, unless and old k98 Mauser can be found.

 

[benchracer]

My #1 has a twist rate of 8.75, easily enough for the 175 EH's and adequate for the Berger 195's (though the case capacity would be a poor match for the 195's). It looks like Ruger has gone to an 8.5 twist rate for their current production 7mm's.

From what I can tell, the movement toward heavier and higher bc bullets (along with better optics, better powders, better barrels, etc. ) has mainly been driven by the civilian market. Much of the driving force behind that came from members and content contributors on this very site (LRH), starting in the early 2000's. These advancements have trickled up to the military, rather than trickling down to civilian shooters. This has been the trend in the US for a long time. The advancement of Heavy Rifle sniping is a good example of this. The civilian shooting community has long functioned as a built in R&D department for the US military.

If the plan is to build a rifle, an AI chamber, with freebore matched to the chosen bullet, would be worthwhile. I would expect a 24" barrel to be a good compromise for a sporter in either 7x57 or the AI version. RWS brass would likely offer the toughness to run at magnum pressure (63k-65k) with modern loads in a modern action.

 

[Calamity]

You may be right about the direction of technology flow. Either way, it's a good thing. Innovation is good.

My first rifle (1958) was a 95 Spanish Mauser. In 1960, I built a 7x61 Sharpes & Hart. I killed a whitetail buck at 600 yds with that gun. Longest hunting shot I ever made. Made a 7mm Rem Mag in 1976. In 1982. I built a 7x57 featherweight for my wife on a Herter's FN Husqvarna action. The powder selection then was IMR or Hogden 4831 or 4350. Maybe some 3031 and 4895 for lighter bullets. Sierra 160 and Hornady 162 gr were about the only decent BC bullets. 44 gr of 4350 would push the Hornady to 2495 fps in her gun. I have owned other calibers, but the 7mm has always appealed to me. If I build another, I'm leaning toward a .280AI. I did not know there was a 7x57AI. Where can I find ballistics?

 

[benchracer]

I have owned other calibers, but the 7mm has always appealed to me. If I build another, I'm leaning toward a .280AI. I did not know there was a 7x57AI. Where can I find ballistics?

Data and ballistics for the 7x57AI are hard to come by, if you don't have Quickload. The 7x57AI would have case capacity almost identical to .284 Win, so looking at that data would give you an idea of the level of performance one could expect from the 7x57AI. As a rule, though, the short and fat cases (such as the .284 Win) tend to do their best with powders a bit faster in burn rate than longer cases of similar capacity.

 

[JMW67]

The 1892, 7x57 Mauser is, I believe, the parent pattern case for most of the rimless American cartridges, such as the .308, 30-06 and .270 Win. I'm talking about head dimensions. SAAMI lists max chamber pressure for the 7x57 at 50,000 CUP, and for the 7mm-08 at 60,000 CUP. The .280 Rem, 30-06, .270 Win all run about 60,000 CUP or higher. I understand that ammunition makers load the 7x57 at around 46,000 CUP because there are some old M95 small ring mausers still in use, that might not stand the higher pressures. Does anyone out there load the 7x57 to 60,000 psi in a modern rifle, and if so, what kind of ballistics do you get? The 7x57 has greater case capacity than the 7mm-08, so it should out perform the '08.

loading the 7x57 like you are speaking of for modern firearms it is on the heels of the 280 rem or 284 win I had one in a ruger number one it was a cool rifle to hunt with

 

[Calamity]

Thanks, guys. I found this:

7 X 57 ACKLEY IMPROVED

There are several 7x57AI forum discussions, including some discussions in this LRH forum: https://duckduckgo.com/?q="7x57AI"+ballistics&norw=1&t=ffhp&atb=v113-1&ia=web
But very little actual test data. The anecdotal consensus appears to be that the 7x57AI duplicates .280 Rem ballistics, and does it more efficiently, with good accuracy. With 180 gr ELD bullets it equals a factory 180 gr 30/06 @2700 fps MV, but as the range extends the higher BC 7mm retains velocity and energy better than the '06. According to one user, it is still supersonic @1000 yds with 1000 ft-lbs of energy. One thread touts the 7x57AI as a frequent build for F-class competition. Another claims his 7x57AI pushes 139gr bullets a bit over 3000 fps from a 24" barrel. It seems that the popularity of the 7mm-08 is simply the lack of promotion/knowledge of the 7x57, which is still popular in Europe and other countries. According to the bullet makers, a 1:8 twist appears optimal for the 175-195 wt bullets.