chuck375,
The ballistic comparison shown with the visual comparison is just a generated table from actual load data submitted by members,
what is actually being loaded and chronographed by those who have posted at:
www.ammoguide.com
Just averages of some light loads for the 500 Jeffery, apparently.

Yep, I need to load up the 500 Mbogo data with some hot loads to make it surpass the 500 A-Square.

Perhaps I should join ammoguide and upload hot 500AHR loads to surpass both the 500A2 and most likely RIPS 500Mbogo. How about 570grainers at around 2550 fps. That is over 8200 ft-lb of muzzle energy. It kicks pretty darned good too even with the brake.

FOOBAR,
Excellent analysis. I agree with you ... mostly.
The new case that has been once fired is what is most appropriate, for us handloaders to do our computing with, as you say. Thanks for making my point for me.

Ah, thanks for the correction guys. It's nice not to see Dinosaur stopping loads for the 500 Jeffrey on the web for a change. My 570g TSX at a relaxed 2100 fps went through a dead computer then 7 gallon water jugs, 1 1/2" of plywood finally stopping in a 5 gal bucket of sand. It did shed it's petals though ...



Chuck

Big bore cartridge brass is always undersize for the chamber,
as it comes from the maker in loaded ammo or component form.
New-unfired versus once-fired can vary a grain or two.

The last time I looked at the 500 AHR, the brass came from Bertram.
They never could entirely get rid of the rebate on the rim either.

RIP,

All my 500 AHR brass is Bertram, and most of it is good. It is thick as hell at the head, but not soft, which by the way, is how one would want it for a double rifle (longevity thing some probably wouldn't understand). The rim is slightly rebated in that the rim diameter runs around 0.595" with a base diameter of 0.6195" on average. No problem getting 600gr pills over 2500fps, but the recoil is a bit too much for hunting, at least for me. I load it to ~ 2440 fps with 570gr pills and ir kills very very well.

By the way, for equal pressure it beats my 500 A2 by about 120 fps (barrel is 3" longer though so the real figure is closer to 75 fps). I would figure your 500 Mbogo should beat the A2 by at least 60 fps equal pressures/barrel lengths.

I load the A2 to about 60 ksi which equals ~2320 fps with a 570gr SN. I don't trust any of A Square's pressure data for THEIR proprietary cartridges, BTW.

Keep stirring the pot.

I personally like the .500 A2 the best out of the bunch, a great "no nonsense" approach to a .50 caliber hunting cartridge.

Probably not likely to enduce nostalgia, or romance a shooter of the purist persuasion, but it's just so damn easy to work with.

quote:

Most of the data is good,
but some of it is systematically bad data.

The gross water capacities are fictitious.
The 500 Jeffery drawing they have shows it to have a 30 degree shoulder. Just watch out for bogus data there.

For example, the water capacities of real 500 Jeffery and 500 Mbogo (aka 50-08) are both about 155 grains.

AmmoGuide case capacities are estimated by a common algoritm. There is no one "correct" value for case capacity. It is a GENERAL GUIDE only. An empirical measurement depends on many factors such as whether the case is "fired", "unfired", or "fired and sized" (and whether neck or full-length sized), whether the case contains internal "soot" or is clean, whether the primer cup is blocked or filled, altitude, temperature, brass thickness, brass manufacturer, etc etc etc. Because water is very dense (56,000 gr./gallon), such variables can cause much greater variation in measuring case capacity than is normally expected. Those who expect exact values for case capacities and try to define it to tenths of grains are involved in an exercise in futility, no matter how carefully they conduct their measurements.

The algorithms on AmmoGuide for calculating case capacities have been tested and found to be accurate and concistent from cases as diverse as the .22 Hornet to the .50 BMG. The REAL value of this approach is that ALL CASES ON THE WEBSITE ARE EVALUATED AGAINST THE SAME STANDARD. Because of this, AmmoGuide is one of the few places on the planet where case volumes can be compared consistently and without the abovementioned variables introducing comparison error.

AmmoGuide shoulder angles are exact where known, estimated where not and noted as such. Many cartridge submitters do not provide shoulder angle. The accuracy of this calculation can be affected when only 3-digit precision is used to define the shoulder geometry, particularly on rounds with small shoulder.

The only problem I have with any of the posts here is the tendency to INCORRECTLY advertise that AmmoGuide is "systematically" in error by shooters who don't understand the issues of defining and listing cartridges en masse. Such issues are best resolved directly by logging into the site and using the "Support" link under the "Personal" menu. That is, if you believe a given dimension or shoulder angle to be incorrect, just let us know. We try to be very responsive to such queries. But please do not go off posting on other forums that AmmoGuide is "systematically" in error when it is not the case. Our main function in life is to insure the saferty and accuracy of the information on AmmoGuide. That's why we verify every SAAMI-registered round against that organizations database.

quote:

Originally posted by RIP:
chuck375,
The ballistic comparison shown with the visual comparison is just a generated table from actual load data submitted by members,
what is actually being loaded and chronographed by those who have posted at:
www.ammoguide.com
Just averages of some light loads for the 500 Jeffery, apparently.

Yep, I need to load up the 500 Mbogo data with some hot loads to make it surpass the 500 A-Square.

You might want to consider that extremely light loads (like subsonic loads in a normally supersonic round) are rejected by the Ballistic Comparison Tool as anomolies and not inculded in the computations.

However, your average light load (i.e., a few hundred fps below normal) will be factored in.

All normal and heavy charges are included. (There is no "anomoly" decision made on the high end.)

Mike Haas:
Thanks for finally taking the time to address this.

Long ago I tried the support internal to your site.
My inquiries about your gross water capacities, method of calculation, went unanswered, and I just quit bothering.

Your algorithm cannot possibly cover the internal structures of various cases.
No way.
You should not even try to represent them as relative case capacities in gross water.

You might rather eliminate the fudging and just list the volume based on the external case measurements,
or the weight of same case if it was made of solid brass, like Dr. Ken Howell has done in his book.

So, you check against SAAMI?
But you do not check against CIP?
That explains why you have the 500 Jeffery shown with a 30-degree shoulder.
That's the semi-angle you show for the 500 Jeffery, i.e., equivalent to 60-degree junction cone angle.

The 500 Jeffery shoulder semi-angle is 12.6 degrees, i.e, the shoulder angle is 12.6 degrees per side, to the nearest tenth of a degree. Go there to get the minutes and seconds on the brass.

O.K. I'll quit calling your case capacities "systematically erroneous" but I will continue to say that I have not found a single one that would be useful for internal ballistic estimation.
All of yours seem to be on the low side.
That seems systematic to me.
But I won't call it systematic anymore.
I will call it "calculated by algorithm, and not proportional to reality."

Just what percentage of the total exterior case volume does your "algorithm" apportion to the internal structural brass volume?

Is it the same percentage for every make of case?

Some other references like QuickLOAD and AccuLOAD do not have the same systematic "estimation" on the low side.
They have over and under estimations, but in general are much closer to some actual brass measurements that I do.

Yes, we all understand the difference in different makes of brass, and different conditions,
and even the difference in new-unfired versus once-fired-and-not-resized brass.

Everybody but FOOBAR.

Mike,

Calculating case capacity is not difficult at all. I have an Excel spreadsheet that nails it every single time +/- 5 grains of water NO MATTER what shoulder fired case you are using. The error comes ONLY from wall and web thickness variations that can exist from case to case and manufacturer to manufacturer. If the cased is sectioned and these dimensions are actually measured the calculation will be on to +/- 1 grain!!

RIP, it ain't that hard to model the internal case structure of a case. It is actually quite easy!!

I find your case capacities to be GROSSLY in error for the cartridges listed on this thread. I am sorry if you disagree with me.

Have a nice day.

ScottS,
Why in heck would I want to calculate gross water capacity of brass?
I can measure the actual gross water weight contained by the actual brass that is fired in my actual chamber.
My brass, my chamber.
The brass expands to fill my chamber at peak chamber pressure, then springs back to smaller than it was at peak.
Before being resized, it is still a little bigger than new-unfired brass when I measure it,
but it is in the state that is best for basing QuickLOAD calculations upon.
That is the gross water weight that I am interested in.

RIP,

Just to clarify, I understand what you want for your internal ballistics calculations. I was simply stating that the Ammoguide method is significantly flawed and really could be "fixed" quite easily. Calculating a case capacity, with reasonable accuracy, ain't rocket science.

RIP:
And there you were, doing sutch a great job for so long ignoring that clown.

Bent,

What did I do to you? I also was not "attacking" RIP either so I just don't understand your post.