I’ve hunted with various muzzleloaders for almost 40 years. And almost exclusively with a muzzy for big game all over NA and Africa for 25 years or so. My personal (first shot) limit is usually 200-250 yards with open sights. Guys with better eyes and the right load/sights should have no problem (with practice) at 250-300. With the caveat that you can’t “spray and pray” like guys do with centerfire. You have to wait for the right shot.
Here’s an example of a modern load in a modern rifle - a verified drop chart for my open-sighted .45 WA G3 this season - 80 grW Bh209 and a Fury 225 gr bullet/HLBS. Wind drift and drop (even with a 100 yard zero) is manageable out to 300. And energy is more than adequate for deer (1445 ft/lb at 300).
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