I know this is not the easy answer, but the best I can figure is it depends on the combination of your rifle, your load, and you. I know many here will disagree, but I trust mine to 200yds, with me, and not the gun or load, being the limiting factor. I do agree that somewhere between 125 and 150yds, range estimation becomes very important, so if you just want to hold dead on and hit, 125yds sounds very good, but this can be stretched out if you can or are willing to learn to estimate range correctly. The .45 caliber slug weighing 250+ grs will penetrate much more than people would expect, so the trajectory becomes an issue long before the bullet runs out of steam. Take it out and see what you can do with it as each of us is different. I thought I was good, til I got into an informal match using coke cans and milk jugs for targets. We both stayed on coke cans to 150yds, but started shooting at the jugs at 200yds, and I started missing at 250, with my furthest hit being at 325, but that was one out of several shots. He on the other hand, was still getting first round hits when we ran out of ammo at 375-400yds. I know I cant shoot like that yet, but i'm trying to learn.