If you plan to use BH209, i strongly feel you would be wasting your $ if you bought into the 25acp conversion. It is my opinion that the chance a rifle, or pistol primer would ignite BH209 at -10, without a delay, is virtually zero.

In an Omega, the W209 primer should provide 100% reliability igniting BH209 at -10, or in the rain, and do it with zero blow back.

If you are trying to reduce the 'crud ring' whilst using 777, and/or improve accuracy whilst using 777, you may find the 25acp conversion worth the investment.