Practical Accuracy Tip
When you're at the range, and it doesn't matter if you're on a square or field fire range (where you can move or take up more realistic firing positions), make sure that you load your mags with random brands and projectile weights of ammunition, especially in the AR family.
Doing so simulates 'battle field pick up' which is what we're going to have to look forward to someday before any of us realizes.
Sure, it's nice to have ammo supplies that we use the same projectile weight, lot numbers, and manufacturers, but I guarantee you, when SHTF, and you're running low and you 'happen' to some across a body with a few AR mags in a fire fight, you're going to grab them and go. Hopefully, you'll be experienced in the different points of impact, high or low, when that happens and can adjust.
NOTE: The above implied scenario is for when you're actively in a firefight. If you come on 'bonus' ammo around the bend of some road, remember the old SE Asia trick our own people were reputed to use: Take a full AK mag, pull the rounds about 1/3 to 2/3 out, take one round, pull the bullet, dump the powder, and take a bit of C4 and stuff into the case, then re-seat the bullet, load it into the mag followed by the other rounds, and leave it just as they found it. When an enemy troop happened to find that mag, and then use it, and fire that round, catastrophic failure and injury/death would occur....or so I've been informed.