So technically, it is not a true straight-walled cylindrical case like, for instance, the. When thinking about wildcatting possibilities of this new case, I asked myself what could be the largest caliber bullet that we can stick in this case if we completely straighten it up leaving no case body taper. 366 caliber (9.3mm) bullets should fit just perfectly. 366 is an odd European caliber, however, many US companies are making bullets in this caliber which I assume are mostly used in the 9.3圆2mm cartridge. For example, if you visit the MidwayUSA website, you’ll find out that they currently offer 23 different. 366 cal bullets made by Hornady, Speer, Barnes, Nosler, Woodleigh, and Swift. In order to load the bullets designed for the 9.3圆2mm to the same seating depth in the new cartridge, we’ll need to have the same space for the bullet over the case (OAL/case length difference). If we subtract that from the 2.26″ length of AR cartridges, we’ll get an optimal case length of 1.41″. 350 Legend case to a truly straight-walled cylindrical shape, shorten the case to the 1.41″ length and load with. 366 cal bullets designed for the 9.3圆2mm (loaded to the same depth), we’ll get the largest caliber and arguably most optimal dedicated subsonic cartridge that can be created using the. 350 Legend load ( Super Suppressed) with 265-grain bullets, the. 366-350 will allow loading bullets with longer ogives and theoretically achieve better ballistic performance.

There should be enough space left in the new case to stuff enough powder that will allow pushing the 250-grain bullets just shy of being supersonic (remember, the. 350 Legend case is designed to operate at 55,000 psi pressure). In fact, I am pretty sure that the heavier 286-grain bullets or even the heaviest 300 and 320-grain bullets can also be successfully loaded to achieve around 1,000 fps of muzzle velocity. I know, experimenting like that sounds like the most redneck way of determining the useful case capacity and powder charge volume compatibility with any particular bullet length/weight at a given seating depth, but if it works then it is rocket science! The load development may require playing with the bullet length, weight and powder types to find perfect combinations of bullets and powders. The performance of such a cartridge should be very close if not identical to the 9x39mm except in an AR platform, with a standard. 223/5.56 bolt and in a more compact straight walled case. One downside is that forming the new case may require more skills, tools, techniques and operations than it sounds like. For example, blowing it up to a completely cylindrical shape can only be done using custom tools or fire forming the case. The shortened case may require trimming the wall thickness of the new case mouth.

And of course, the most obvious disadvantage will be the lack of case taper which will make it more challenging to feed the cartridge and extract the case in semi-auto firearms.įind Firearms Chambered in. 224 caliber cartridge that will have the same case length as the.

223 Remington and will allow using the same standard. 223/5.56 bullets, however, due to the slightly thicker case body, it will provide a bit higher case capacity thus becoming ballistically superior cartridge compared to the. The same concept can be applied to create the “improved” versions of. 223/5.56-based cartridges such as the 25-45 Sharps, 6x45mm, etc.

350 legend subsonic ammo