Steel case ammo is fine. The most important part of steel based ammo is the jacket of the bullet. It is Bimetal, so it will be "harsher" on a barrel than typical brass cased ammo. Steel does not expand and well as brass, so you will "need" to clean the gun more as it will get dirtier. The Echelon is a supremely made gun with a hammer forged barrel. All in all, steel cased bimetal jacketed ammo, might decrease barrel life some, by not by a margin that would really make a difference. Pistols are lower pressure low velocity=less barrel wear overall.
Most people have a budget in mind when shooting. Some use high quality defensive ammo all the time. I am in the mindset that trigger time is most important and one can buy a bunch more steel cased than brass cased.
Do not plan on having steel cased FMJ for your carry load, use a HP. Buy a few boxes of defensive ammo, like HST or Winchester Ranger, run them to validate, and keep enough to have two mags full.
Winchester M1152 is pretty serious stuff aswell, like +p+
For training go cheap.
What have you been running in you Echelon
@Astro14 ?