I do not really hunt with mine. I don't run steel in my Auto-5 (the shooter), so I bought a Beretta A-400 Extreme for my waterfowl gun. But since you asked about lead, I use Winchester AA and Remington STS and Nitro 27's... mostly #7.5 and #8 shot, since I do a lot of hunting the fast, orange birds (trap). Still, I have a reserve of four or five flats of Federal paper hulled shells. There's just something about shooting an older firearm with the paper hulled shells in the crisp Tennessee winters.
Well then...since this question is not about hunting... Then this thread should be in either the Ammunition sub forum or the Browning Auto A-5 sub forum. Since you reference your FN Auto-5...I shall move it there.
If you mean what functions in an Auto-5, I like Federal, Remington, and Rio. I avoid Winchester Universal and Herter's. I'm sure the more expensive ammo will work, but why throw money away?
Yes basically what do you trust not to Efup your beloved FN Browning. For example, is nickel plated lead acceptable and if so what do you use? If not, then what? I am looking for more specific loads not just the big brands. I recently was gifted a 1945 Auto_5 and do not want to risk a barrel issue using the wrong ammo.
I've never used nickel plated shot; I don't know but I doubt it would do any harm. I didn't think it was used outside hunting applications.