Ok so this is a stretch and a bit of just playing around. While messing about on Chat Gpt I gave it a proper asking it to create the most ballistically superior cartridge that will fit in a mini length action (Howa mini/ CZ 527) in the 6mm bore size. And it came up with one called the 6mm mini short magnum or 6mm msm. These are the theoretical specs it created:
Concept: A radically shortened, fat-body “WSM-style” case (~1.60–1.65" case length) with either a rebated rim (.445" to use Grendel bolt) or a true magnum bolt face (.532") if your mini action can be re-bolted/opened up. Seat 105–115 gr bullets to ≤ 2.30–2.35" COAL.
Sketch specs (target values)
I basically want to know how possible this is, can it be created from an existing cartridge like 243 wssm, and should I build one for shits and gigs instead of a 6mm ARC. My thoughts: if I’m already going to pour money into a full custom rifle with dies and components for the ammo why not go all out? Main downside for me is no factory ammo available, and possible feeding issues. I wouldn’t mind going to a short action but want to avoid just jumping for a 6 prc or a 6 creed just because I want to be difficult on myself.
Concept: A radically shortened, fat-body “WSM-style” case (~1.60–1.65" case length) with either a rebated rim (.445" to use Grendel bolt) or a true magnum bolt face (.532") if your mini action can be re-bolted/opened up. Seat 105–115 gr bullets to ≤ 2.30–2.35" COAL.
Sketch specs (target values)
- Option A (rebated): .445" rim, ~.530" body, 35–40° shoulder
- Option B (mag face): .532" rim, ~.550" body (bolt/lug thrust rises a lot)
- Case length: ~1.60–1.65"
- COAL: ≤ 2.35" (you’ll need custom magazine/follower)
- Capacity (gross): mid-40s to low-50s gr H₂O after seating
- 115 gr class: ~3,050–3,150 fps possible on paper
- 105–110 gr class: ~3,150–3,250 fps
I basically want to know how possible this is, can it be created from an existing cartridge like 243 wssm, and should I build one for shits and gigs instead of a 6mm ARC. My thoughts: if I’m already going to pour money into a full custom rifle with dies and components for the ammo why not go all out? Main downside for me is no factory ammo available, and possible feeding issues. I wouldn’t mind going to a short action but want to avoid just jumping for a 6 prc or a 6 creed just because I want to be difficult on myself.
