[sholling]

I know that the battle zero question has been beaten to death - I've searched and yes it has. But all seemed to be generalities and did not take into account the velocity, weight, and BC of the bullet. I know that 5.56 charts all presuppose a given round.

I've spent some time with Big Game Info's External Ballistics Calculator and come up with some fairly decent numbers to work from. Based on these numbers I'm thinking that a 150yd zero is about right for this civilian. That looks pretty good to me for both defensive and hunting purposed out to 250yds. I'd like some expert opinions because I'm far from an expert on ARs and a novice at 6.8 SPC. My weapon is a AR15Performance Xtreme with 1:11.25 twist. (pictures to follow later in the week). Thoughts and opinions?

Starting Point:
I've taken SSA's statement "6.8 SPC 110 grain Sierra Pro Hunter Ammunition, 20 rounds/box. 2575FPS 100YD/1.3" 200YD/0.0" 300YD/-8.7" 16" BBL, 1-10 twist" and used the velocity estimates.

These suppose a 110gr projectile with a ballistics coefficient of .314 and a muzzle velocity of 2575. A sight height above bore axis of 2.5" and altitude of 1000ft and a nice windless 60 degree day. Oh and 1/2 MOA adjustments.

100yd Zero

150yd Zero

200Zero

 

[owenslee]

150 yds is a reasonable choice and would certainly work in most situations.

But for me...I like a 200 yd zero over one at 150 yds.

I am willing to accept an additional 1.6" of bullet rise on a target at only 125 yds in order to gain over 3" less bullet drop on a target at twice that distance.

Kerry

 

[paulosantos]

It depends on how far youa re shooting at. For 0-300 Yards, I still prefer a 100 Yard Zero as it is nice and simple.

 

[Red Monkey]

All of my rifles are sighted in 2 in. high @ 100. That way I always know where they are going to hit, even at 300 yds. From 0-200 yards you will see a point of aim change on a target but NOT on an animal. That deer, pig, elk or what ever will have a hole 'right where you put the cross hairs' on its hide cause there an't no scoring rings on his hide, just brown hair. The kill zone of most big game animals is about 'pie plate' size so 2 in. high @ 100 yds works for me and will keep a shot inside that kill zone at any distance I care to shoot. I have taken deer at 300 yards but don't make a pratice of it unless the conditions are RIGHT, no wind at all and a good solid rest. For must hunters, not military snipers who practice a LOT at long distance shooting, a 300 yard shot is pushing the envelope. On several occasions I have used a range finder to check hunter X's 350 yard shot and discovered it to be around 200 yards, sometimes less, yet he will swear it was 350 yards!!. Must hunters and shooters can't judge distance and would be well servered with a 2 [email protected] 100 zero as it is a little more forgiving when the shot is longer than 'guesstimated'. If you guys don't agree, hey that's OK with me but this is a time tested zero that works in the real world without any 'dial turning' or 'second guessing', just set the cross hairs in the target and squeezzzzeee, Mr. Big will be DRT!!

 

[constructor]

For ease and simplicity I would try to keep the Z at even 100 yds increments.
dead on at 50 will usually put you on at 200 but, if you use that set it dead on at 200yds then take a reading at 50 and 100 to get actual holds. That works for CQB or hunting in the brush but still gives you some range too, probably be 1.5" high at 100 and 150, easy to remember.

I always use a 300 Z but I tend to shoot longer distances than most and I am not a twister for what I do these days, I use the reticle mil/moa hash marks to hold over or under.

 

[sholling]

Thanks all after reviewing everything I'll shoot for 200m when I hit the range next week.