milling and dialing turrets, am I doing it right?

[JAnderson94]

Hi guys. Yesterday I was shooting at what I believe was 320 yards. Shooting crappy fmj ammo to get some brass for reloading. They chrono about 3,075fps out of my ar. I am using a vortex hst 4-16x44 with mil reticle and mil adjust. I just swapped scopes so I zeroed at 20 yards then went to 320. I was holding two mills high to hit at 320. So is my math right when I use. .36" as 1/10th of a mil at 100 yards. Then times that by 21 clicks (what I used when I dialed and stuck crosshairs on target instead of holdover.) Then times that number by 3.2 for the 320 yards I'm shooting??? Because that's a hair over 24 inches and that seems like excessive drop at 320 yards for a 223.

Edit: forgot to add that scope was set on 16 power also
Thanks,
James

 

[Bravo 4]

I would definately say something is wrong, if you zeroed dead nuts on at 20 yards the bullet won't cross your line of sight (actual down range zero) again till past 300 yards!
Without knowing your bullet or any other particulars about your set up or environmental conditions I would bet that just about any 55/62gr FMJ (most are FMJ-BT) at that speed under about any atmospheric conditions would have a zero of around 300 (+/-) yards. Minus 2 mils of drop would be more like over 500 yards...some closer to 600.

 

[JAnderson94]

Well I walked it yesterday and it came out to 450 yards or so. So redoing my math I got 35.5 inches of drop. The hornady ballistics table said 38 inches with the load data I gave. Being that its 2-3 moa ammo at 100 I would say that's more then close enough at 450 yards. Looks like my range finder might be a little on the inaccurate side...

 

[Bravo 4]

That could have something to do with it.

 

[JAnderson94]

Always the small details that get a guy!