Quoted:
I usually shoot 55 gr and 62 gr federal and pmc ammo out of my bcm midlength upper 1/7 twist. I've never gotten a chance to try out any heavier loads and was wondering what the POI shift would be like If I started shooting 69, 75, or 77 gr ammo? Is it a significant change in impact? If you use heavier ammo for hunting/self defense but train with lighter stuff what do you have your gun zeroed for?

Quoted:


Out to 100 yards, most people find very little difference between the POA/POI regardless of whether they are using 55 gr FMJ or 75 gr OTM. My go-to load is the Federal 62 gr Fusion, and I practice with 55 gr AE223, Wolf, or whatever is available. I can even get hits on fairly small targets using my Fusion zero with the cheaper practice stuff at even 200 or 300 yards. The POI difference generally isn't more than a few inches. For training purposes that is good enough for me.

That said, if you are wanting to do really precise shooting where an inch or two makes a significant difference, this approach may not work for you. But if your goal is to zero with a really good load for HD while using whatever cheap stuff is available for combat type training, you'll find they are more than close enough to accomplish what you want at reasonable distances.