They have,

.375/350gnWoodleigh@2300,300gn@2475,270gn@2675,235gn@2850
.416/410gn Woodleigh@2250
.404?
.458?

and claim that they all operate at no more than 46,000psi for any of them. But I recall the 35 Sambar with 250gn@2700, pressures were much much higher than 46,000 I believe,plus I dont see any other WSM cartridge flinging its pills out at such a low pressure. So how do they do it? or is it just plain BS?

Woodjack ,
It's all about expansion ratio which is basically the ratio of case capacity to bore diameter .
There's a big hole in the end of the barrel with these cartridges which allows gases to escape more quickly and keeps pressures down . If you do the geometry you'll see that the internal volume of a .416 barrel is about 90% higher than that of a similar length .308 barrel .
You may have seen that Federal / Sako have introduced a new .338/.308 that is more powerful than a .30/06 albeit using a smaller case . Same principle .

So the "ideal" is a straight case with a belt on it to give you your headspacing?
Cheers...
Con

I spoke to the bloke peddling these creations at a Sydney gun show.
He was most convincing-he reckons one of his first sales was to a rep. from Winchester Australia who was going to
send it back to the USA from testing.

I must be a boring kind of guy as the standard run of the mill rounds 22/250, .30/06, .375 H&H etc. suit me pretty well.

My only deviation from that is a Rem 700 .300 RUM.

Wombat, can you fill me in on these new wildcats please? I have had a play fiddling with the WSM case necking it up and down to various calibers. Who is the guy behind these creations?
thanks Malcolm56

Con ,
Not sure whether you're taking the piss or whether yours were serious questions ?
That's the trouble with e-mail I guess !I don't claim to be an expert on what's ideal but the trend is certainly toward short , fat cases as the 6mmPPC type design has proven to have accuracy advantages . The WSM's are supposed to be loosely based on the PPC design concept .
Headspacing on the belt is not a recommended practice from an accuracy standpoint but with a straight walled case the choices are either the belt or the rim .

BushChook,

A 35 SAmbar with 250gn@2700 which I read somewhere, was operating upwards of 55,oooPsi (Con stated once somewhere that operating pressures were estimated between 55-75oooPsi) all of a sudden becomes 46,oooPsi when you go to .375 bore with 270gn@2675? I am not convinced.

Bushchook,
Yeah sorry I was being a little tongue in cheek. The point I was trying to make was that if you take the "necking up" for efficiency far enough, you end up with straight cases, then you need a way to headspace. At each sizing up though your losing sectional density in the projectiles you use (ie 200gr .35 vs 200gr .30) which is a disadvantage, hence the beauty of the lighter mono-bullets which hang together. I also think the gains that the WSMs make are due to the pressures they're being run at compared to older designs. The PPC has a lot going for it though, excellent close tolerance brass, reamers, dies, barrels, projectiles, experimentation etc... I'm not sure you couldnt get its accuracy from a conventional case if you could control the quality of everything together.
Woodjack,
Regarding the 35WSM, I have no idea what pressure they ran to get their velocity, but the data in Guns & Game wasn't pressure tested to the best of my knowledge. I think Troutman once stated that in his 270WSM you need to run fairly stout loads to get the necks to seal (nice heavy brass! ) and stop sooting. Given that pressure signs may not necessarily show until 70Kpsi are reached ... who knows what pressures the 35Sambar ran at? Hey ... given the great brass in the WSMs, and modern steels, who is to say that 70Kpsi is now unreasonable...???
Cheers...
Con

So a saboted projectile out of a larger calibre will get extra velocity and maintian SD.
A short fat case with a shoulder just big enough to headpsace effectively. Large calibre and just alter which calibre projectile and sabot you use.
Technically the perfect all round rifle. 22 sabots for small game, 308 sabots for medium game and full size projectiles for large game.
I am just joking around but as a concept it could be a good one. There are plenty of problems to work out and it wouldnt do much for gun sales so its not a good idea for the big companies.

Woodjack ,
In the absence of test rifles chambered for the cartridges mentioned and also not having any equipment for measuring pressure I have no comment . I was talking principles not specifics .
WSM's are designed to work between 60000 to 65000 PSI anyway so who cares as long as they're within those parameters ?

Bushchook,

I suppose principles can be discused here with no harm to anyone, but when people try to market a wildcat to the public I see specifics as being somewhat more important. Further more, part of their marketing pitch is based on the "low pressure loading principle", yet when I spoke with them they could not explain how they achieved or how they were able to confirm that low pressure figure. I asked if they had a pressure barrel test rig,they said "No". I said so how then?....they said,well....you can just sorta' tell.
I am sure Dakota spent the time and money to do proper pressure tests with proper equipment before they released their 404 Based line of cartridges, rather than just a bit of guesswork in the garage on a Saturday afternoon. Bush mechanic principles are fine for the farm,but not the loading bench.
What kind of confidence would it instill if you asked Rem or Win. what they load a particular round at, and they said, we are not sure but we guess somewhere around 46000-65000psi cause we dont really know. Dont think it would happen.

It all reminds me of when I had ARB fit a TURBO&Intercooler unit to my diesel LandCruiser.
The promises/warranty were fine until the engine blew cause of incorrect installation, among other things(suspension) that failed also through their installation.They all of a sudden wernt interested in the customer.I can tell you that ARB warranty aint worth shit when your stranded in CapeYork,even when you find an ARB dealer, who refused to help me cause he had a personal dispute going with Sydney.Another major Point is that ARB never have and probably never will do anywhere near the R&D that Toyota does. My failed installations are living proof of that.Backyard mechanics with fancy marketing. Same goes for the Australian stalker Rounds from what it sounds.

Woodjack ,
If the explanation that they gave you re. pressure was as good as they could do then I understand where you're coming from . To make a statement about 46000 PSI and have nothing to back it up is obviously ridiculous .
Maybe good cartridges (?) but the company could use a more professional approach .