Capacity of 6.53 scramjet and .257 STW

[M8ball]

I was looking around on the net for a case capacity for the 6.53 Scramjet.  I was curious how much more capacity this thing had relative to something known like a .25-06 or .257 WBY.  I also didn't have any luck finding data on the .257 STW.

Anybody out there got a fired case in these calibers?

[The Sodbuster]

Don't know about the Scramjet, but the .257 STW is based upon a necked down 8mm Rem Mag, so case capacity would be similar to that. 

[nomosendero]

The case cap. is a little more, not sure exactly how much because I have heard too many negative
things about the Lass. brass quality. To me why build a rifle of this type that you want to be accurate & not have a source of quality brass?

The 257STW is a screamer, no doubt. It is 200-300FPS+ of a 257Wea. if long barrels are used. To me, if I wanted a round faster than the Wea. & a conventional twist & normal weight bullets, I would look at the 25-300Win. Mag. Your barrel life will be better than the STW, yet your vel. is close.
Comparing to a 257Roy, you have cheaper & plentiful brass & you can get better quality brass as well. Data for STW & 25-300 are here:   www.reloadersnest.com     As they will tell you, work up slowly & they are not a reloading manual.

If you want the ultimate in power for a 25 & not shoot it in high volume, you will want the
257 Allen Mag. It uses the 338RUM case straightened & necked down. It is used as a system, fast twist barrel, about 1-8, & heavy bullets. This is the right way to use a big case with the 25 bore
as opposed to using conventional bullets in the Lazz. This round is designed to shoot a 156 Gr. Wildcat at about 3,300FPS (yea, 156) & it will trump the conventional bullets at long range. If you really want a big 25, I can PM the info, no I have nothing to do with it, but I know of it & it's capabilities.

 

[M8ball]

Thanks for the info.

To clarify, I'm not actually in the market for a fast .25.  My interest is in cartridges that aren't grossly overbore (.308 Win, .250-3000, etc.).  Not to say that if a .257 WBY or the like wandered by at a good price I'd turn my nose up at it...

I'm just doing a number crunching experiment for various 25 calibers for which I've got max working pressures to see how capacity and velocity interrelate.  I've read John Barsness' article in Handloader from a few months back on converting data from one cartridge to another and wanted to see if it made sense within one caliber range.