Reliability is key.
My neighbor, who is a retrired instuctor from the police academy, advised me to get a pistol very dirty. At least 200 rounds.
Then fire 100 rounds of the "duty" type ammo without cleaning or lubricating the pistol.
I purchased 4 boxes or the 185 grain Remington +p and proceeded. (I hadn't realized how expensive this type of ammunition is) Both my 1911 and my SIG 220 passed this test with the Remington ammo.
That is why my .45s are loaded with it..
Perhaps even more importantly, I learned how to conduct a good reliability test.