Range Report Actual Zero

[Deleted member 10043]

After shooting several 10 shot groups at 100 yards I determined the zero is really on average .28" low @100 yards based on everything. I want to know what the close to true zero is for my shooting. Rather than bullet path I looked at bullet drop and it looks like about 90 yards. Am I doing this correctly?

Bullet drop @100 yards = 2.53"

2.53" - .28" = 2.25" = approx. 90 yards

Bullet 168 .308 .218 BC MV=2620

The only reason I'm even doing this is because I use different ammo that is the same caliber and bullet weight. My favorite ammo is a good consistent 100 yard zero. The example above is more of an inexpensive practice ammo shooting at the same 100 yard target. I usually just add a click or two depending on the range for the cheap ammo for correction. Moving the target to 90 yards and repeating the whole process is not economical.

 

[The Mechanic]

Re: Actual Zero

Are you trying to do a parallel bore zero for the calculation? Otherwise I am not really sure what it is that you are asking for. Zero is zero. If you are .28 low put another 1/4 click in if you are IPH.

 

[Deleted member 10043]

Re: Actual Zero

Sort of a parallel bore zero. Yes, zero is zero for one particular type of ammo. Take a different brand with the same bullet weight and different MV and you get a different zero at the same 100 yard target. In this case the bullet is rising to the target in relation to bullet path (LOS) but not bullet drop (LOD). It's easy to calculate this when you have room. Example, a bullet shooting low .48" @ 200 yard target may have a 186 yard zero. I used these numbers based on the Exterior Ballistics module of the Silhouette Ballistics program. However, SB cannot calculate low .28" at a 100 yard target because the bullet is too low at the target distance (100 yards). The calculator cannot come up with a solution. Regardless, the premise is still the same whether it is .48" low at a 200 yard target equals actual zero of 186 yards and .28" low at a 100 yard target = x yards.

 

[kraigWY]

Re: Actual Zero

Want an accurate, honest zero.

Set your your target at a given range. (use the same target each time).

Shoot one shot every day for 5 to 10 days. From a different position, (prone, setting, bench, standing, across the hood of a car, from inside of a car, etc). Each day record everything, position, weather, light,- everything.

After you shoot your desired number of days, (the more the better) take your target and draw a line from 12 to 6, and from 3 to 9 o'clock. Count the number of shots in each quarter to see where you are. Now adjust until you get the same number in each quarter.

This is critical in LE counter sniping where the first shot is the one that counts. It also is handy for a hunting rifle.

You're not gonna get the itty bitty groups you see on the internet, but you'll get honest groups to get you an actual zero.

 

[Deleted member 10043]

Re: Actual Zero

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: kraigWY</div><div class="ubbcode-body">Want an accurate, honest zero.

Set your your target at a given range. (use the same target each time).

Shoot one shot every day for 5 to 10 days. From a different position, (prone, setting, bench, standing, across the hood of a car, from inside of a car, etc). Each day record everything, position, weather, light,- everything.

After you shoot your desired number of days, (the more the better) take your target and draw a line from 12 to 6, and from 3 to 9 o'clock. Count the number of shots in each quarter to see where you are. Now adjust until you get the same number in each quarter.

This is critical in LE counter sniping where the first shot is the one that counts. It also is handy for a hunting rifle.

You're not gonna get the itty bitty groups you see on the internet, but you'll get honest groups to get you an actual zero. </div></div>

Man, that advice rocks! Thanks so much.