The "6.35x28.6mmSR Stewart", or '6.35x28.6mmSR', or '.25ALS' is a Modern Conversion Cartridge based upon reforming 5.7x26mm Cases to .276"-278" Body diameter and Trimming to nominal 1.125" length, leaving the Rim and Extractor clearance grove about the same as the parent Cartridge case.
This Is proposed as:
- A Modern way to get The Firearms Chambered in ".25 Stevens" or ".25-10-67" as Winchester, Marlin and others termed it 'Speaking Again' since the Original cartridge is 'Obsolete', no longer commercially loaded, and examples are 'Collectible" and Priced Accordingly.
- A case that is far Stronger than the original RF cases, as the Parent is rated for use at 50,000psi Maximum Average Pressure by CIP.
- A new Cartridge to use in Small frame Revolvers but with more Potential than the .22WMR.
- A New Cartridge that can be used in Strong Rifle actions to its Full 50,000psi MAP potential with a wider Range of Bullets and OAL lengths.
This Cartridge is published as cartridge number 958 in the "Ammoguide International" 'Cartridge Master Data Base'. It is Similar in dimensions to the Previously Published "6.35x32mmSR" (published as number 950 in the Same Data Base) and to the "25-10 Halsted" (a Wildcat designed for .257" Bullets).
It is Easier to form, but requires more tooling, than similar designs made from .22 Hornet Parent Cases.
The Yield from Forming is better than that experienced from Forming from .22 Hornet to the Same End Body diameter. (My experience is about 5% loss when forming .22 Hornet to .276 body Diameter and ZERO Loss when forming 5.7x28mm to .276 body diameter.)
Forming Cases to these diameters is discussed in other Threads on this Forum so the details will not be repeated here unless Requested.
For Revolvers, bullets should be loaded to limit Overall Cartridge Length to fit the Cylinder, or 1.400" maximum and about 1.395" is a slightly better 'target length'. A range of bullets commercially available can be extended by Resizing bullets down from .257" diameter to .250"-.252" diameters, depending upon bullet type and construction.
Best Regards,
Chev. William(Cartridge cases That is.)