Ballistics, am I reading this correctly

Thread starter #1

j_seph

Senior Member
Used Federals online calculator. I do not have a long range to go shoot at. But from what I am gathering, if I am sighting in at 25 yards I need to be 0.4 (13/32 :) )inches below center to be dead on at 200 in a perfect world or dead on at 35 yards.
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Offroadtek

Senior Member
The unknown is usually your velocity. Real life is never the same as manufacturer data. But by confirming the drop at the distances you can test at, you'll be able to build a chart for your specific rifle.

I bet you'll find that your drop at 200 is a little more than this chart since real world velocity is often slower than what the chart says.
 
The mystery is the actual muzzle velocity of "Your" rifle .... What the box says may be close ....it may not be .... anything else is a guess ...

To be real close ....you would need how high above the center of the bore your sights(scope) is ... temperature ... humidity ... air pressure ... altitude ... the bullet BC ... the bullet weight. ....the bullet caliber and the muzzle velocity .... and if you are shooting up/down hill ...the angle of the target ....

With out all the above information .....it is a guess ... if you have all or most of the above you can be pretty dang close to real world ...
 
Forget charts, online calculators etc etc. If you want to be on zero at 200 then the only way to do so is to zero at 200, Period. No way possible except luck for the average guy to have a rifle zeroed at 200 and be "dead on" using charts and having only fired at 25 yards.
I wouldn't even trust a 100 yard guess at zero having only fired at 25 yards. we owe the animals we hunt more than that.
 

ChidJ

Senior Member
So, if we are talking about being truly precise, what others have said is true. But to add to the convo, in the Army, you zero your M4 at 25 and, much like your drop chart, you can get hits to 300 with a dead on hold. Beyond that though, forget about it.

You didn't mention what your purpose was. I'd say if you've got something belt/drum fed, this is a good way to zero if you don't have access to a longer range. I hope you have something belt fed haha
 

bullethead

Of the hard cast variety
Ballistic charts are like Bore Sighting. Both will get you close but you have to shoot targets at the distances you will take shots at while hunting.
A rifle might put all the bullets in one hole at 25yds and the group maybe 8" at 200.
The only way I would rely on a 25yd sight in would be if I already knew what a rifle and bullet does at 200yds and I knew what that same combo did at 25yds...then if I needed to shoot it at 25 due to a dropped rifle, I'd know where it should be.
 

Evergreen

ΜΟΛΩΝ ΛΑΒΕ
I actually fact checked a similar situation with the hornady app for a 308, you plug in barrel, load/round, scope height, and mine was zero at 42 for zero at 200, actually measured it off to exact distances and it was very spot on. I was surprised at the accuracy for several different rifles. But I'm leary to trust only a close zero, fun to play with the app at the range
 
I think what matters at any zero distance is how precise your group of shots fall into the target ...

An example would be if you used a 2" orange dot at 25 yards and you put three shots some where in the orange dot ....then your chance of having a longer distance zero are very slim at best ..

Now if you used a 1/2" dot at 25 yards and all three shots landed in the dot ...your chances are better than the above 2" dot ....

Now to be even more precise the bullet holes(3) would almost have to be within one bullet hole diameter and that hole in the center of the 1/2" dot ...

Any error at 25 yards is multipled by four at 100 yards ... by eight at 200 ... the error keeps multiplying right on out to where ever you target is ...

Just remember that the smaller a target is at a distance ....the more likely for a person to shoot a better group at that distance ....
 

killerv

Senior Member
I always start at 1in low @25 and then move out to 100 and adjust from there.

I would not trust a centerfire rifle sighted in @25 and then assuming all we be ok at further distances based on a chart or whatever else.

You need to make every effort to find a 100 yard range. Is there not a place at your club or lease to shoot 100 yards?
 

killerv

Senior Member
keep in mind, you wont notice 1/4" at 25 but you will at 200. it'll be 2" or more. please take the gun to a range of at least 100 yards and check it.

and then take in the affect his guns probably 3in group at 100, which translates to 6 at 200 and you still dont know what part of the target its gonna be on.

Had all year to prepare and wait til just before deer season
 
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