There are several good companies out there that make retention holsters for the Springfield Armory Echelon. A Google search will bring up a plethora of good companies .

Try here: https://wethepeopleholsters.com/products/springfield-echelon-4-5f-with-surefire-x300u-a-light-red-dot-optic-cut-owb-holster?variant=41487356461154

Try rounded by concealment. That's who I use with my Echelon.
roundedgear.com/?srsltid=AfmBOoqK6HJLQudQ2DK2SjWjFXK1ed9ZbcCnnqMbDQsO8xywODypcKt9

Here ya go!!!
Springfield Echelon 4.5 Red Dot Optic Cut OWB Holster https://share.google/wdvGpFbVhbf0RrZqT

Hi Michael and welcome. I highly recommend "We The People" and "C & G" Holsters. You should be able to easily configure a OWB Holster: -- https://wethepeopleholsters.com/products/springfield-echelon-4-5f-with-surefire-x300u-a-light-red-dot-optic-cut-owb-holster?variant=41487356461154 ----------------------------------------- candgholsters.com/products/springfield-echelon-4-5f-owb-covert-kydex-holster-custom-c-g-holsters?srsltid=AfmBOoox06rhR-I0tIKp5i10tOXOhgru_HCU3ceBnx5Ll1kkKng7Sn7Q --------- Cheers and stay safe!