Bullet drop variation

[KsRancher]

My dad has a 300 win mag and he bought some 178gr ELD-X precision hunter. We shot it Saturday and Sunday. Looked up a ballistic chart off of Hornady website for a rough idea. Here is my question. Is this possible? Or something wrong on our end. His bullets didn't drop as much as it showed on on Hornady website out to 400yds. 500yds his dropped more than Hornady calculations. And at 600yds back to dropping less than Hornady calculations. It seems to me that your gun would either shoot them and they would all drop more or less than Hornady calculations, but not both ways.

 

[hereinaz]

It is possible but as a scientific question I would start eliminating possible human variables and other errors as a process of working out how it does that. (Edit to add that the solver can spit out what seems to be error, but it’s not the solver itself.)

Input errors or other variables are the cause of many errors in modeling.

What are the actual numbers and what were the conditions of the shoot and range?

 

[LaHunter]

Are you not dialing your scop and measuring actual poi drops at the various distances? What is your procedure for measuring drops? If dialing, could be a scope issue

 

[wind gypsy]

How big were the groups @ 400, 500, and 600 yards, how many shots were in each group, and how high/low were they?

 

[Turkeytider]

This is timely. I shot some Frontier ( Hornady ) .223 68 grain at 500 yards. Those rounds were hitting a full MOA below where the ballistic calculators ( Hornady and my Kestrel ) said they should be. On target after I adjusted up. Don`t have a chronograph, but did make we wonder if the stated muzzle velocity was off.

 

[wind gypsy]

This is timely. I shot some Frontier ( Hornady ) .223 68 grain at 500 yards. Those rounds were hitting a full MOA below where the ballistic calculators ( Hornady and my Kestrel ) said they should be. On target after I adjusted up. Don`t have a chronograph, but did make we wonder if the stated muzzle velocity was off.

Muzzle velocities vary by barrel length, chamber, individual barrel bore dimension/condition, and with temperature. Not to mention there is frequent significant variance lot to lot of the same ammo. So yes, the stated muzzle velocity is almost always "off".

 

[Turkeytider]

Muzzle velocities vary by barrel length, chamber, individual barrel bore dimension/condition, and with temperature. Not to mention there is frequent significant variance lot to lot of the same ammo. So yes, the stated muzzle velocity is almost always "off".

KInd of makes me look at calculators as primarily a good " guide ". Sort of like bore sighting to get you on paper. A starting place.

 

[TaperPin]

Also, past a few hundred yards, head winds and tail winds, not to mention a curl of wind coming over a shooting enclosure, ridge or side burm can do crazy things to elevations.

 

[hereinaz]

This is timely. I shot some Frontier ( Hornady ) .223 68 grain at 500 yards. Those rounds were hitting a full MOA below where the ballistic calculators ( Hornady and my Kestrel ) said they should be. On target after I adjusted up. Don`t have a chronograph, but did make we wonder if the stated muzzle velocity was off.

The box velocity is most certainly off. At best it is a starting place. Adjust velocity down until the dope is right and keep testing the info.

 

[KsRancher]

I will post the figures when I get home and get them in front of me. But I didn't think about that wind coming from the tail being a cause for elevation changes. It was from 0-10 mph direct tailwind

 

[wind gypsy]

KInd of makes me look at calculators as primarily a good " guide ". Sort of like bore sighting to get you on paper. A starting place.

They work great with good inputs and a user with an understanding of how they work.

If you have your inputs correct and properly working equipment, you should be able to just adjust MV to true at 500.

Thing is you can have up/down drafts, aerodynamic jump, and atmospheric things impacting it as well.

 

[hereinaz]

KInd of makes me look at calculators as primarily a good " guide ". Sort of like bore sighting to get you on paper. A starting place.

Long range shooting is more art than science.

I think it is best to consider it a tool that is only as good as the information given so it can predict.

But, with sufficient skill and even basic technology the ability to make reliable impacts out to 700 is within reason.

 

[hereinaz]

I will post the figures when I get home and get them in front of me. But I didn't think about that wind coming from the tail being a cause for elevation changes. It was from 0-10 mph direct tailwind

Shooting should be looked at as an experiment, so you are learning and now, you can test this and then make adjustments “by feel” based on exactly this experience.

It is why proficient long range shooters preach bullets down range. And, why a trainer gun becomes a thing…

 

[Pharmseller]

You told us about the rifle and ammo but not the scope.



P

 

[Turkeytider]

Also, past a few hundred yards, head winds and tail winds, not to mention a curl of wind coming over a shooting enclosure, ridge or side burm can do crazy things to elevations.View attachment 623239

I`m pretty well convinced that the things that can impact the flight of a bullet from point A to point B is pretty much limited only by one`s imagination. And the longer the distance to travel, the worse it gets! No wonder I`m inconsistent with a 4" gong at 500 yards!

 

[TaperPin]

I will post the figures when I get home and get them in front of me. But I didn't think about that wind coming from the tail being a cause for elevation changes. It was from 0-10 mph direct tailwind

Not all of the elevation change will show up in a ballistic calculator with head/tail winds, because of up/down draft of the air. It sounds wrong at first, but it’s not uncommon to shoot cross wind to get a better vertical group measurement, even though the group will string out sideways.

Stream fishermen are good at visualizing air flow, because air currents look and behave just like water currents along a river or stream bed - the scale is just larger.

 

[Turkeytider]

Long range shooting is more art than science.

I think it is best to consider it a tool that is only as good as the information given so it can predict.

But, with sufficient skill and even basic technology the ability to make reliable impacts out to 700 is within reason.

" Long range shooting is more art than science . " Don`t know if everyone agrees with that assertion, but I`m personally beginning to think there`s a lot of truth in that. Sometimes I feel like there`s a definite degree of SWAG in it!

 

[TaperPin]

I`m pretty well convinced that the things that can impact the flight of a bullet from point A to point B is pretty much limited only by one`s imagination. And the longer the distance to travel, the worse it gets! No wonder I`m inconsistent with a 4" gong at 500 yards!

That’s for sure! A 4” gong is pretty small at that distance.

 

[wapitibob]

I take the KISS approach; zero at 200, shoot 400 and 600 then adjust bullet speed in ballistics app to match 600. Shoot a few more groups at 600 then to 1000 and finalize the speed. With 200 and 1000 good, 600 won't be off enough to make a difference if it's off at all. Certainly not on a hunting rifle.

 

[KsRancher]

Here are the numbers. The 500yd drop is the one that doesn't make sense. Going to try again next weekend and see if we can replicate it. This was shooting with the center crosshair only. We had a tall target and just let the bullets fall. Then we measured with a tape measure. No dialing or holding over. I am not worried about their numbers not matching ours. Just can't figure why ours aren't consistent