The 357 Rimless Mag cartridge is not available in
the featherweight or lightweight barrel profiles.
This cartridge is formed by blowing out 223 brass to straight and trimming to 1.29"
We sell trimmed commercial 223 brass for $25 per 100 pieces.
357 magnum loading data is available in any loading manual.
Velocities in an AR15 will exceed the lever action data that is commonly available because the AR15 is good for 50K PSI.
Most Rifle data in the loading manuals is for 35K PSI pressure. Start with book max loads and work up from there.
This chambering is not available in standard grade due to availability of barrel blanks.
This cartridge is still in development and may be restricted to spire point bullets due to feeding concerns.
Left->Right: 9mm, 357 mag, 357 Rimless Mag, 30 Carbine, 223 Rem Rounds fit standard AR mags