7x57 versus 7-08

[oldcelt]

I agree with comments in post #23. I have an old handloading guide from the mid 30s by Phil Sharpe and there conciderable differences in loads for both guns

 

[1948CJ2A]

Hey now dont go taking me out of context. That suggestion was for a non-reloader. The examples I listed in that thread are from comparable loads from the same manufacturer. I have a 7x57 and not a 7mm-08, I believe in the old mausers capability. If you will refer to post #2 of this thread, I note there is not a whole lot of difference (since you handload as you imply in the original post).

Sorry firesky. Not trying to ruffle feathers. Your comment about the 7x57 being 400 fps slower than the 7-08 in comparable loads (assuming factory ammo) was an example of the common misconception on the differences between these two rounds. Even if one doesn't handload, when choosing a rifle, wouldn't you want something with more potential? Who knows perhaps someday that person might get into handloading and make use of the extra case capacity.

Of course the problem today is that the 7x57 is not nearly as common as the 7-08 in new rifles. And because of that, I can see why you would recommend that to a newbie or someone looking for one deer rifle. Still if I could have only one hunting rifle, I'd say the 7x57 would be near the top of the list.

 

[firesky101]

Its alright, I just did not want to people to think I did not like the 7x57. The other thread was dealing with a specific problem for someone who does not reload. I am sure with handloading you can far exceed the hornady loadings for either cartridge.

 

[GooseGestapo]

According to Lee#2, the useful volumn of the 7mm08 is 3.32cc.
The useful volumn of the 7x57 Mauser is 3.68cc, or a 10% difference.
Hence, at the same pressure, the 7x57 will get 2-3% more velocity, if everything is equal, but it never is.....

Also, everyone "knows" the .308 is vastly inferior to the .30/06.... (not!). Because it has a 22% lower "useful" case capacity.... 3.43cc vs. 4.38cc.
As most know, the difference between the .30/06 and .308 is only observable with a chronograph with bullets 180gr or heavier.....

Looking at my Lyman#48 manual, they list 8 loads with the 7mm08 getting 2,800fps or more with a 139gr bullet and a 24"bbl. and one gets over 2,900fps . With the 7x57 they list 3 loads getting 2,800fps+ and that's with a 29" bbl.....
So much for the supposed "much greater potential" of the 7x57..... Like I said previously, IF everything is equal, the difference is perhaps 30-40fps in favor of the 7x57. Or, about like the standard variation between one shot and the next.... from the same box of ammo..... Truly insignificant !!!!

Why don't we "argue" over something really significant; like how many angels can dance on the head of a pin.........

 

[1948CJ2A]

Goose - in post 14 you said:

The difference in case capacity is nearly nil. Actual net difference is about 3-4% with that even varying between make and lot# of cases.

Then today you said:

According to Lee#2, the useful volumn of the 7mm08 is 3.32cc.
The useful volumn of the 7x57 Mauser is 3.68cc, or a 10% difference.
Hence, at the same pressure, the 7x57 will get 2-3% more velocity, if everything is equal, but it never is.....

So how are you figuring 10% more case capacity yields 2-3% more velocity? Or is that just based off your reloading manual?

 

[RickMD]

The difference is the same as between the .243 Winchester and the 6mm Remington. One functions in a short action and the other has a longer neck and is more conducive to reloading. Other than that there isn't enough difference between them to concern yourself about.

 

[Lone Star]

The late gun and hunting writer Jack O'Connor liked the 7X57mm and one was his wife's favorite rifle.

BUT...he went primarily to the .270 because the 7mm was usually throated for 175 grain bullets and using it with shorter bullets tended to wash out barrel throats sooner.

On the other hand, those longer, heavier bullets are the sole advantage that the 7X57 has over the 7mm-08, and in factory ammo, the newer round is normally loaded hotter, unless you get Euro ammo or some special higher velocity ammo from the few companies who offer it. Both Federal and Hornady have done this high velocity thing, but I forget what they call those loads. I think Remington may also have their version.

Today's barrel steels are tougher than what O'Connor encountered in the 1930's-1950's, so I don't know how soon using 139-145 grain bullets might wash out a modern barrel throat.

BTW, I guess everyone here knows that the famed .275 Rigby is just a 7X57mm loaded with Rigby's patented bullets, which were genuinely better than most in their day. Of course, Karamoja Bell used full jacketed bullets to kill those elephants that he shot with 7mm rifles.

 

[interlock]

both are great rounds.

the 7mm08s case shape and design may make it more efficient with faster burning powders where as the 7 x 57 has a longer case and different shape that may make it better with heavier bullets and slower powder.

7mm bullets have really good ballistic coefficients (broadly speaking).

both are excellant proven game killers

 

[oldcelt]

I fail to see what has been proven by this dicussion.
My hunting partner hunts with a 7m/m 08 and I with a 7x57 but at the end of the day the results are equal,the quarry was swiftly dispached.

 

[1948CJ2A]

I fail to see what has been proven by this dicussion.
My hunting partner hunts with a 7m/m 08 and I with a 7x57 but at the end of the day the results are equal,the quarry was swiftly dispached.

My reasons for writing this thread have already been stated. Sorry you didn't get more out of it. Perhaps next we'll do a 243 Win versus 6mm Remington thread and everyone can say how both are equal. I of course will argue that all day long.

 

[GooseGestapo]

10% capacity vs. 3-4% velocity increase is simple physics. And my earlier comparison was not based on actual published capacities but my experience with comparing the two based on my experience with the 7x57 with brass that was mil-spec/mil-suplus from the '60's in comparison to the current factory 7mm08 brass. Current commercial 7x57brass has approx. 5% greater volumn than the mil-spec brass I had experience wtih. Hence, I used Lee's published data..... in the subsequent posting....

With an upper limitation of 65,000psi chamber pressure due to limitations of brass and gun steel, an increase of 10% more powder, or approx 4.5gr of powder in the case of 7x57 vs. the 7mm08 ususally only results in a net increase of 3-4% velocity. Several writer/technicians have written treatises over the years documenting this phenomenon. It applies to any cartridge comparison....

It's why it takes the .300WinMag case to get a significant increase in performance over the .30/06. Whereas the "little" .300Savage comes within 3-6% of the .30/06 with bullets 150gr and lighter..... And explains the origin/developement and existance of the 7.62x51 aka 7.62 Nato, aka .308 which is the parent case of the 7mm08.....
I actually have no preference between the two cartridges other than the rifles that are available.

However, in the case of the 7x57Mauser, factory pressure levels are held to lower limits than with the 7mm08.
For a more similar ballistic comparison of the two, look at the Speer #8 manual. They load the 7x57 to 50,000cup and the 7mm08 to 52,000cup or very close. But, then the 7x57 has a 22"bbl vs. a 24"bbl for the 7mm08, which results in the 7mm08 giving higher velocities on the average of ~100fps.....
Like I said, it's never a 1:1 comparison, even in the best of comparisons.....
And of course we've done nothing but restate and rehash the obvious.....

 

[1948CJ2A]

10% capacity vs. 3-4% velocity increase is simple physics.

I'd like to see you formulas for this statement. Assuming both rifles are shooting identical bullets, operating within the same max pressure limits (both modern rifles), and assuming identical environmental conditions. My experience with college physics and projectile motion was never simple. To calculate this accurately you would have to do the formulas and conversions by hand, as using computer software and/or reloading data will be skewed with differing pressure tolerances (as previously covered in this thread). I'm not saying you're wrong but I'd like to see the math you did to come up with those numbers. You can work backwards using simple math. Taking 4% of 3000 fps (just an example) would be 120 fps. That seems logical but like I said before, to really figure out the relationship between case capacity and MV, you'd have to setup multiple complex physics equations to truly get a scientific answer.

For a more similar ballistic comparison of the two, look at the Speer #8 manual. They load the 7x57 to 50,000cup and the 7mm08 to 52,000cup or very close. But, then the 7x57 has a 22"bbl vs. a 24"bbl for the 7mm08, which results in the 7mm08 giving higher velocities on the average of ~100fps.....

According to SAAMI, for velocities between 2501 & 3000 fps, barrel length increase per inch yields approximately 20 fps additional MV. So adding 2 inches using this information yields a 40 fps advantage, not 100 fps.

Like I said, it's never a 1:1 comparison, even in the best of comparisons.....

I agree.

Hey at the end of the day here, like I've said multiple times already in the thread, both are great rounds. And the difference between the two is minimal in the grand scheme of things; however, I'd like to think that these minimal improvements were part of the driving force behind the great efforts from folks like P.O. Ackley.

 

[Haxby]

"... 10% difference... at the same pressure... will get 2-3% more velocity..."

Yep.

 

[35 Whelen]

<snip>
It's why it takes the .300WinMag case to get a significant increase in performance over the .30/06. Whereas the "little" .300Savage comes within 3-6% of the .30/06 with bullets 150gr and lighter..... And explains the origin/developement and existance of the 7.62x51 aka 7.62 Nato, aka .308 which is the parent case of the 7mm08.....

I understand the point you're trying to make, sort of, but the 300 Savage does not come within 3-6% of the '06 with 150 gr. bullets...more like 15%. On the other hand, the '06 comes within 7-8% of the 300 WM. So the '06 is quite a bit closer to the 300 WM than the 300 Savage is to the '06.

As I stated in an earlier post, I've never loaded a 7mm-08 but have load the 7x57 quite a bit. In my Dad's 700 Classic, a 139 gr. Hornady will do a little over 3000 fps (roughly 4-5% over Hodgdons 7-08 published data with the same bullet). A 154 gr. Hornady right at 2900 (5-6% over Hodgdons 7-08 data ). FWIW, I used this load for my first bull elk. Both these loads were chrono'ed a few times over the years on first a Pro Chrono then later on a CED.
My old sporter'ed Venezuelan with a 22" tube would run a 150 gr. Nosler SB at 2889 with one load, 2915 with another...roughly 5% faster than the 7-08.
So seriously, in the field there's maybe 50 yds. difference in the two, right?
Are we splitting hairs yet?

35W

 

[1948CJ2A]

On the other hand, the '06 comes within 7-8% of the 300 WM. So the '06 is quite a bit closer to the 300 WM than the 300 Savage is to the '06.

This has to do with cartridge efficiency. There is that analogy of the law of diminishing returns (economics). When you have a cartridge that starts nudging into the overbore category, it begins to take increasing amounts of powder to see minimal gains in velocity. A good example of this is the 7mm STW. Nosler did a write-up on this in their 6th Ed Reloading manual.

Neither the 7-08 nor the 7x57 fall into this category. And I agree with you in reference to the 300 Savage vs 30-06 percentages. I have looked at the comparisons in a couple of reloading manuals.

And yes we are splitting hairs.

 

[denton]

In a modern firearm in good condition, there is no reason that you cannot operate the 7x57 at 30-06 pressures. The firearm cannot read the headstamp.

John Barsness' rule, which seems to work well, is that if you get X% more case capacity, you'll max out at 1/4X% more muzzle velocity. So by that rule, 10% more case capacity gets you 2.5% more MV. Estimates of 2-3% are right on in the case of the 7x57. All other factors equal, the 7x57 will always exceed the 7-08, but not by enough to make much practical difference.

The 7x57 works perfectly in intermediate length Mauser actions, like the Yugo 24/47 or 48. If you're converting one of those, 7x57 is a better choice than 7-08.

The 7x57 does seem to have a small advantage with heavier bullets. In my instrumented 7x57, I get 2750 FPS with a 162 grain bullet at pressures in the mid 50 KPSI range. That's a very capable hunting round.

They are both outstanding rounds. I would not feel undergunned with either of them for just about anything in North America. I have a couple of 30-06s, but rarely shoot them since I built my 7x57.

 

[1948CJ2A]

John Barsness' rule, which seems to work well, is that if you get X% more case capacity, you'll max out at 1/4X% more muzzle velocity. So by that rule, 10% more case capacity gets you 2.5% more MV. Estimates of 2-3% are right on in the case of the 7x57. All other factors equal, the 7x57 will always exceed the 7-08, but not by enough to make much practical difference.

The rule he uses is called the 4-to-1 Rule. Here's a link to the article where he describes this rule: http://findarticles.com/p/articles/mi_m0BQY/is_4_55/ai_n31392893/

If you applied his rule to this debate, you would have to use the 7-08 published MV since he's using factory & reloading data (assuming identical pressures in 2 modern rifles). According to Remington's factory ammo ballistics table, the 7-08 pushes a 140 gr at 2860 fps. The case capacity of a 7-08 is 55 gr. The 7x57 capacity is 60 gr. By dividing 5 (the difference in capacities) by 55 (the smaller 7-08 case), you get 9.1% more capacity in the 7x57. Applying his 4-1 rule, you divide .091 by 4 and get 2.3%. If you multiple 2.3% by the 2860 MV of the 7-08, you should see a MV increase of approx 65 fps in the 7x57 (everything else equal). If you wanted to use reloading data and used 3000 fps as your starting point on the 7-08, you would get a 69 fps increase in the 7x57 (everything else equal). Increasing the MV of the smaller round increases the difference in fps between the 2 but the percentage stays the same of course.

I'd still like to see the math this guy used to come up with his 4-to-1 rule. It would seem to me that all cartridges would be slightly different. Plus if the smaller of the two cartridges you're looking at has a lower SAAMI max pressure, then this rule won't work. Example of this is the 300 Savage versus the 30-06 Springfield. If you apply his rule, you come up with 7% increase in MV for the 30-06 over the 300 Sav. If you multiple that by the published 300 Sav Remington factory load (2630), you get 184 fps. Add that to the 2630 and you get 2814 fps. But then reference the 30-06 (same table) and you'll see a published MV of 2910. That's almost a 100 fps difference. This is because the 300 Sav max pressure is 47,000 psi versus 60,000 psi in the 30-06.

One more example and then I'm done. If you look at the 30-06 versus the 300 Win Mag and apply his rule here, you end up another 100 fps shy of the actual Remington factory table data. I'll show the math again if someone wants to see it. The SAAMI max pressure differences between these two cartridges is 5,000 psi (much less than the 13,000 psi diff between the 300 Sav and the 30-06). Interesting...

How does the 1/4 rule apply to the overbore cartridges? It would seem that using just one rule of thumb for projectile motion would be rather obtuse. It might get you pretty close but it doesn't take into account different max pressures. In college physics I remember there being 4 different equations for linear motion. You had to examine the specifics of the experiment in order to determine which one or which combination of them you needed to use. I would think this to be no different.

 

[denton]

Barsness is a very capable fellow, but math and physics don't seem to be his strong suite. This is most likely an empirical formula.

Just looking at it from an energy standpoint, you are converting the chemical energy of the powder into kinetic energy of the bullet. But kinetic energy is .5*mass*velocity^2. So you'd expect muzzle velocity to go up as the square root of the ratio of available energies. Assuming the 7x57 has 10% more case capacity (for round numbers), you'd expect a muzzle velocity change on the order of square root 1.1, or 1.048. That exceeds John's rule, but not by a lot.

The real situation is undoubtedly more complicated than this. You have more surface area to rob more heat energy out of the propellant gas for one thing.

 

[1948CJ2A]

The real situation is undoubtedly more complicated than this.

Yea. In the end the 7x57 Mauser has greater potential and yields greater muzzle velocity and energy than the 7m-08 (assuming everything else equal including max pressure in modern rifles). It may not be much but the increase does exist. Based-off the information provided in this thread, those results should be apparent.