Hey guys! Haven't made a post on here in quite a while. So anyway I'm asking for advice on what distance to zero my 16-inch 9mm AR for USPSA PCC. I'm using an Aimpoint ACO as my optic. Thanks!

I have my AR pistol zeroed for 25 yards which puts me within 2" high or low between 0-60 yards with my reloads. Should be plenty flexible for USPSA. You can run the math using JBM ballistics website if you know your height over bore and a rough BC for your bullet and velocity.

I run a 100 yard zero on my PCC's works out to around 20 yards with my ammo. I suggest you spend some time at the range to select a zero that works best for you.

I run a 50 yard zero and have been pretty satisfied with that overall. I still occasionally don't get the offset right on very close shots but that's not a zero issue.

I used this calculator to determine a 25 yard zero was likely the best for most rounds I will use in my AR pistol with a 10" barrel: http://gundata.org/ballistic-calculator/ Then I tested it out on the range.

This will likely be what you'll want for the 16" barrel also.

Others have reached a similar conclusion: http://web.archive.org/web/200...ersSite/9mmzero.msnw

With most lighter (115gr) bullet loads you'll be within 1.5" of your "dot" between 25 and 100 yards, and with most heavier (147gr) loads you'll be within approximately 2" of your dot between 25 and 100 yards. Obviously at very short ranges you will need to account for "mechanical offset" between the dot and the bore.

I have mine with a 25 yard zero, which is also supposed to be "on" at 100. Effectively a 25-100 zero.

It seems to be, but with my eyes, and iron sights, I can't confirm that the zero works perfectly.

It’s a uspsa gun, the average shot is going to be 12-15 yards. I’d zero at 15 because you might actually see a 15 yard head box and poa/poi would be beneficial for shooting alphas there. Where as the most difficult shot you are going to see at 25 is likely going to be a mini popper or a tuxedo, in which an inch or two in vertical impact difference isn’t a big deal.

Don’t forget to figure out your hold over on hoser distance head boxes. You might actually have to aim over the target to hit an A.