Lest we forget, the "Short-Fat" technical idea.

While the attributes of short-fat design are correct as identified here, what stands out as very ugly in this article is the declaration [Jamison's "short fat" patents are the basis for the Winchester Short Magnums and the Remington Short Action Ultra Magnums].
I believe the WSSM/SAUM designs were the basis for Jamison's stealing rights to them, with application and approval of patents -that were no more than broad descriptions of that already existing and manufactured.
A possibly all time low for the shooting world...
 
While the attributes of short-fat design are correct as identified here, what stands out as very ugly in this article is the declaration [Jamison's "short fat" patents are the basis for the Winchester Short Magnums and the Remington Short Action Ultra Magnums].
I believe the WSSM/SAUM designs were the basis for Jamison's stealing rights to them, with application and approval of patents -that were no more than broad descriptions of that already existing and manufactured.
A possibly all time low for the shooting world...
Also, an all time low for the US Patent office. While there was plenty of "prior art", the legal cost to contest the patents would easily exceed several years of any profit gain to the party contesting the patent. Add to that, the chances of overturning an issued patent is very low. Jury's and judges are useless with technical fights. As an aside, when first introduced, I bought a 223WSM and a 270WSM. Accuracy and ballistics were great but both barrels/throats were toasted in less then 500 rounds, and the Winchester brass was garbage after 3-4 reloads. I like, and agree with the attributes of the short/fat cartridge design, but IMO, they perform best when the load is well balanced, and pressures kept in check.
 
Actually the first commercial short mags were the 350 Remington magnum and the 6.5 Remington magnum. They were first marketed in 1965 These were belted and performance was very good, however Remington built them on the wrong rifle format. (The 600 action).

Then in 1975 the PPC became popular with the bench rest crowd.

It wasn't until 2000 that the WSMs were introduced and Remington followed up with the SAUM in 2002.

The WSSMs came shortly after (2003)

In the right rifle and barreled action, they are great performers but like many other cartridges they can be problematic if pushed to hard .

Just a little history of the short mags.

J E CUSTOM
 
I have a 6mm designed by By Smalley of Utah. By was a rocket engineer and knew his business. He swore by the "short fat" rule for all his cartridges up to his 5mm to 6.5mm. By worked with Mick McFerson to develop the 5mm and 6.5mm.
 
I have thought a long time about the "short, fat" profile for rifle cartridges. Long before they became popular -- or even available -- it occurred to me that such a profile would burn powder more efficiently, and that we were too dependent on a very old cartridge design that probably has its roots in other considerations than best burning of the powder.

Some of the wording in the patent application just makes me raise my eyebrows, though. Does a fat cartridge really "place more of the propellent in proximity to the flame front of the primer? While it is true the flame front expands laterally (radially) at the same time it is progressing linearly toward the shoulder of the case, is it really closer (in proximity to the primer) than if it travels only linearly? I think that would have to be demonstrated empirically, and although I think it is probably so, I don't think we really know.

Another statement, though, really strikes me as questionable: "and reflecting more unburned granules rearwardly into the burning propellant where they are consumed." I suspect unburned granules are not reflected rearward in a cartridge case, especially as the flame is moving forward (and perhaps radially outward.) I would guess unburned granules remain in place while the flame front moves toward them.

All this is to question the wording of the patent application, not whether or not short, fat cases are the best. Looking at the historic development of bottle-necked cases from early examples like the .30 WCF and the early Mauser cases, I suspect their development was NOT optimized for burn pattern inside the case. I suspect, rather, that they were just a sort of progression from straight-walled black powder cases, into the smokeless powder realm, with the understanding that smokeless powder burns faster if it restricted -- unlike black powder, whose rate of burn is only dependent on granule size.

If we knew more about what happens inside a brass case we might discover that even shorter and fatter cases were better, or perhaps that the WSSM design is not optimally designed in terms of diameter/length and they are slightly too fat for their length. At the extreme, could the best design be a .30 caliber bullet with a case based on the .50 BMG and only 2.5" long? Conventional wisdom is that such a design would burn out throats too fast, but is that really the case?

Case length has probably been too much a function of the length of a rifle bolt, for example. Note that many early Mausers had 57 mm long cases, whether the bullet diameter was 7, 8, or 9 mm. That does not sound like optimization.

There is probably not much ROI in studying this further, but I for one would be interested in the results.
 
The questions from the previous post are excellent and each factor is well worth considering. The graph shown in the link is where most of these questions are answered, if not separately, as to the net effect of the case dimension on pressure vs time. The radiused shoulders of the Weatherby magnums would be another interesting factor to graph.
 
There are efficiency gains with the short/fat ratio's mentioned -especially while combined with improved shoulders, and overbore designs. This is adjusted for in QuickLoad as 'weighting factor'.
The same adjustment would be made for Gibb's front ignition.

I never understood how folks got to thinking that magnum diameter cartridges are suitable for higher pressures. This is just opposite of reality. And many cartridges with great potential have been muddled away from popular because of this thinking.
Way overbore and mis-design of guns are other issues.

Winchester blew it in offering a 22WSSM and 24WSSM, as they had to know they would be barrel burners. They also failed initially to design their guns for WSSM feeding, and to get enough barrel steel around the chambers. At least Savage got this much right.
Winchester recovered somewhat in offering what they should have begun with, 25WSSM. But they still blew it in that they failed to go to the obvious advantage in 26WSSM.

I built a 26WSSM Imp, and I can tell you there is nothing in this cal that reaches it -overall. I get a nice middle velocity node at 3025fps/65Kpsi, with 140gr bullets, 28" barrel, and 47gr of IMR4350. ANY other cartridge in this cal would need a lot more powder or a lot more pressure to do this. I also have over 60 reloads with my cases -with no FL/body sizing, and it's been clear for a while that I will never have to replace them. It's a custom action and chamber designed (by me) for this cartridge, and that's the difference right there between success and failure in short/fat.

IMO, nobody should be choosing short/fat without an informed planning of beginning, middle, and end. The big gun manufacturers have demonstrated that (through failures). So short/fat should probably stay in the realm of wildcat designs and custom gun building.
As an alternative we have Ackley improving. Pick the right bullet to capacity in this, and you will always have a superior result. It can meet magic ratios as well if you make it do so. Ackley improve a 6.5x47, 140gr bullets, fitted chamber (to new cases), coned breech, fine threaded magnum diameter action to get enough barrel steel around the chamber for very high pressure loads with the fastest powder filling the case. Barrel long enough to reduce muzzle pressures for cleanest bullet release.
A combination of past and future. Could go further still in 260AI with front ignition.
Scale for other cals.
 
There are efficiency gains with the short/fat ratio's mentioned -especially while combined with improved shoulders, and overbore designs. This is adjusted for in QuickLoad as 'weighting factor'.
The same adjustment would be made for Gibb's front ignition.
[snip]
A combination of past and future. Could go further still in 260AI with front ignition.
Scale for other cals.


Mike:

I'd like to hear more about front ignition. Other readers would too, I'm sure.
 
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