Sorry about the scruffy cases.

Question:
So, do you think 7X57R can handle hotter loads just like the rimless 7X57 Mauser can in a modern rifle?

Choices:
Absolutely, no doubt.
The Rimmed might be a little weaker.
They are both about the same.
The Rimmed might be a tad stronger.

 

Are the two cases the same brand? If not, then any estimate of pressure handling is not valid.
How do the web thicknesses compare to other cases of different makes and calibers?
Lots more data points need to be gathered to get any kind of answers. And since I think that no 7mmR brass is made in the US, that one is made to CIP pressures only, possibly. Compared to another case of the same make is an important piece of info.

Interesting to see those cross-sections and, if those cases were absolutely representative, you might say the rimmed version has fractionally more meat.

However, the issue is less the case than the action it is fired in; front-locking bolt actions or falling-blocks will generally flex less than a break action and thus their cases should last longer than the latter's.

Where a rimmed case is fired in such a bolt action (ie a P14 Enfield), it might actually have a fractional advantage in that the rim provides additional obturation.

Interesting idea in theory but realistically what are you planning to hunt that you need to try to beef up a 7X57 (which is perfect in it's own right,IMO).I understand about splitting hairs as I am guilty as well;been doing wildcats for the last 40 years.

I really don't know about the strength of the brass, but hinge action guns are the ones usually chambered for the rimmed cartridges, and if one is going to generalize, hinge action guns aren't quite as strong as a good bolt action. So CIP specifies that the max. pressure of 7x57R is a bit lower than the regular 7x57. I think there is a good reason for this. American SAAMI "7mm Mauser" is another standard, for the rimless cartridge only, and is a very low pressure standard that any 7x57 should be able to handle.

Long, I agree in principal about the actions.

When I look at the brass itself and look about 1/2" up, the rimmed brass is definitely thinner than the rimless. That is where I think the problem lies. Both brass are suitably strong at the primer pocket and base yet in my experience it's the neck that splits or a ring developed above the base by some distance.

I vote for the rimless brass being stronger based on a combination of action and thicker brass about 1/2" above the base.

Given equally strong actions I wouldn't worry about loading the rimmed case to the same pressure as the non-rimmed case.

Well, it theoretically depends on how well the case fits the chamber. Cartridge brass will expand ahead of the web at whatever point the thickness (and hardness) of the brass cannot withstand the internal case pressure; only the walls of the chamber keep it from expanding further. If the chamber fit quite tightly all the way down to the extractor groove of the case, then either case would tolerate similar pressures.

However, chambers never fit that closely, which is why you see a pressure ring just ahead of the web on a fired case. This pressure ring represents the point at which the web is strong enough to withstand the internal pressure and not expand out to the chamber walls. If the case walls of the web are thinner (like those of the rimmed version), then the unsupported web will fail at a lower pressure than a case with thicker walls.

The fact that it is essentially impossible to make a chamber tight enough to support the case near the web is the reason that case walls at the web must be thicker (and harder). Thinner/softer cases at the web will fail at lower pressures.

Now, whether the rimmed case in question is thick enough and hard enough to withstand standard pressures that are safe for the rimless case is quite another question. All we can say is that (given similar hardness and metallurgy) the thinner case will fail at lower pressures than the thicker case.

For this comparison, we have to ignore the actions they are fired in; that has nothing to do wth brass strength. Of course, you have to consider that when loading, but for a purely academic discussion about the brass, it is not germane.
Have to ignore the chamber too; assume equal dimensioned ones; the OP is asking about the brass.. With no other variable involved.
Not real world stuff.
That is why I asked if they were the same maker; the rimmed brass has thicker walls but thinner web; what does that mean? Maybe nothing, maybe something.
Also, think about how brass fails at very high pressure; the primer is the weak link; not the brass case. Once the primer is compromised, then the pocket expands, and hot gas comes out and gas cuts everything. That is how we get 100000 PSI out of tank cannons; steel (electric) primers, screwed in.
P dog said it; given equal everything else.

7X57 R CIP 49313 PSI

7X75 mmMAUSER RIMLESS CIP 56565 PSI...SAAMI 51,000 PSI

Absent the excellent but argumentative answers, the actual answer is NO or ALMOST or....the Rimmed version is weaker by XXXXXX PSI.

Questions like his really CANNOT be answered as they are simplistic and require a yes/no answer that is impossible to give.

In actual fact you need to INCLUDE ALL the variations as this is an apples vs kumquat vs banana vs horse apple comparison. I don't think ANY of us has the equipment to actually, scientifically, safely, accurately and PRECISELY measure the strength of the questionable brass ONLY the few that are actually tested...THEN the results could be statistically adjusted to the lot of brass from which the samples came from...AND ONLY THAT LOT.

You certainly cannot remove one wheel, half a wind screen, two injection nozzles and a fuel line and expect a race car to even get on the racetrack which is precisely what some are trying to do in this link.

A rifle/ammo/stock/receiver/etc is a SYSTEM and has to be treated as such, you can't cherry pick and expect an kind of reasonable expectation of belief.

ANYONE that has reloaded for any length of time can justify whatever they do as long as it hasn't resulted on a blow-up and expiration...and ipso facto develop various theories from that and other experiences. You HAVE to have the complete information package to produce a reasonable expectation of success in WHATEVER question you have to answer.

BUT...the fact remains that even with the internet not a lot of information regarding precision data ever gets out and only for the short time the human memory or other media holds it.

This is the same as the 307/308, 356/358 W and450 M/45-70 arguments that came out years ago and basically the same observations are presented...and the same argument failures...instead of reducing the question to it's basic elements, we have to expand it by adding in our extraneous ego's and needs to be right and blow off the real issue...SAFETY.

It doesn't matter which case is "STRONGER", what matters is what SAAMI/CIP says and until SAAMI/CIP does another strength test for the RIMMED version to update it, it will remain the weaker case, doesn't matter what you or I think or suspect...those cases were STILL MANUFACTURED under the SAAMI/CIP pressure regulations and YOU NOR I are privy to those manufacturing methods and materials.

I always wonder just how many reloaders are doing things that are dangerous because they read some krap on a forum posted by someone that misunderstood some other post by some other person who knew only PART of the story or by some self appointed guru. Sad

Good Hunting

What I am reading is that each piece of brass is manufactured to a specific chamber pressure, right?
SAAMI does not have any "regulations"; all it's provisions are voluntary and are noe necessarily followed.
Anyway, as I said, it is the primer that will fail long before the brass case.

Interesting response. Thanks all.

Lower max pressures from CIP and SAAMI for rimmed over rimless 7X57's are justified. All rifles aren't created equal. Pretty simple. It's not just the cartridge that determines max pressures, it's the type of rifle that "could" be chambered in a 7X57R.

Took the K1 Merkel break action with the locking block that locks into the barrel at the top out today. It has a very tight lock up.
Shot some 7X57R's that were loaded starting at 4 grains under, up to one grain over the NEVER EXCEED load using my Older LEE reloading manual for the 7X57 Mauser cartridge. Bullets were 160 Nosler Partitions. Cases were Norma's, same brand I use in my rimless 7X57's. Each group's load was increased by one grain. Every case was inspected one at a time during each group and checked again when they were all side by side in the ammo box. All were fine and all primers were slightly rounded at the edges with slight flattening elsewhere.
Notice: I don't encourage anyone to exceed any max load and my experience may be different than yours as my gun may be stronger than your gun.

Thanks for voting.
CB

I assumed you were talking about the brass strength; not a rifle's. Since you sectioned the brass. Of course, break down rifle ammo is usually (not always) made to lower pressures.
So, the question is a moot one. You load for your rifle's strength; period.
And the notion that brass made for low pressure cartridges, is limited to that, is false.
If it was true, then I couldn't shoot my Ruger #1 45-70 at 55K psi. Or my 35 Remington bolt action, to 50K psi. And many more examples.

dpcd So, you agree with the question. Got it. Thanks.
Jus' for the helluvit.
From Norma and written below 7X57R ammo offerings.
Verbatim of course.


This is the rimmed version of the 7x57, which was designed and developed for use in break-open rifles and combination guns shortly after the introduction of the 7x57 in 1892. These weapons are very popular for all-round hunting in Central Europe, but needs a rimmed cartridge in order to ensure positive extraction under all circumstances. The 7x57R is a very good choice for this purpose as it operates with a modest working pressure which is a great advantage in the comparatively weak break-open actions that furthermore often are very lightly built in spite of having to contain 3 or sometimes four barrels and intricate lockwork.

Like most rimmed cartridges the 7x57R is slightly less powerful than its rimless equivalent due to the lesser working pressure, but as it is mostly used at short to medium range this constitutes no practical problem in the hunting field. For European hunting it is close to the ideal all-round cartridge. It is powerful enough for moose hunting in Scandinavia and is about ideal for roe deer and lesser species. As it is especially designed for break open rifles or combination guns, few arms using the 7x57R will be seen in the hunting fields of America, but in a pinch it is powerful enough for just about everything - with the possible exception of the largest bears.