For practical shooting in IDPA and USPSA.
This load makes 132 power factor from an OEM Sig Sauer 320 X5 Legion barrel

Bullet: RMR 124 MPR (JHP)
OAL: 1.07\”
Powder: Alliant Sport Pistol @ 4.1gn
Primer: CCI 500

The OAL of 1.07\” is my \”universal\” Cartridge length was used to share compatibility with the 320 X5 Legion and a Glock 17 Gen 5.

I use the Redding competition seating die (with micrometer) which has a concave seating stem.