Riddle me this? Ballistic calc vs reality mismatch...

[Calvin45]

Error in velocity, error in zero, both or a input that shouldn't be.

Did you laser 200y when you zero'd?

This would be my first suspect.

 

[geocodyrgia]

Scope height input was the first thing that came to mind for me as well. It's something I used to just SWAG at until I saw what it did to some of my calcs.

 

[Frogman77]

I would re shoot at 500 again on a different day with different conditions.

mirage, cheek pressure on stock, shoulder pressure, rearward pull into the shoulder all can influence the vertical dispersion.

I would also check dope further As well as closer ranges to see how it lines up before making any assumptions.

if your dope lines up at certain ranges but is off At others, there is probably a bc issue.

In all honesty if I'm within .1mil of water line I usually call it good.

 

[smokey3]

Box test the scope & determine it's ACTUAL inches per hundred yards (IPHY) dialing.
There are not a lot of scopes that actually dial in true moa.
I know NF NXS does not, while Leupold Mk4s do.

Just a 5 degree difference at 500 yards will make a world of difference. So instead of calculating for 500 yards you would need to calculate for 498 yards. That's A 6' difference in drop.

Are you sure about that? 6 feet is a lot of drop.

 

[Stgraves260]

Are you sure about that? 6 feet is a lot of drop.

Yes sir I'm sure. I use it all the time.

 

[Stgraves260]

My 260 Remington with 140 grain Berger's have 24.75 MOA's of drop. But convert that to inches it's like 259". People get stuck on the MOA's and Mill's on there dope but forget about the actual inches.

 

[Rooks]

Have you done a tall target test to check scope tracking and level?

 

[smokey3]

My 260 Remington with 140 grain Berger's have 24.75 MOA's of drop. But convert that to inches it's like 259". People get stuck on the MOA's and Mill's on there dope but forget about the actual inches.

I believe you meant 6 inches instead of 6 feet. There is no way a bullet will drop 6 feet in 2 yards at 500 yards, is there? Asking for a friend

 

[Stgraves260]

I believe you meant 6 inches instead of 6 feet. There is no way a bullet will drop 6 feet in 2 yards at 500 yards, is there? Asking for a friend

No sir 6 Feet.

 

[Stgraves260]

I thought we were talking about cosine. If shooting a target at 500 yards with only a 5 degree angle. You would need to calculate your bullet drop for 498 yards. That is a 6 foot difference in bullet drop on you calculations.

 

[Stgraves260]

I thank to many people are using these high tech rangefinder that do all the math for them and don't realize all the calculations that are involved.

 

[Stgraves260]

My 260 has 41.70" of drop at 500 yards if shooting flat and not up or down hill. My dial up is 8 MOA's

 

[Stgraves260]

So teach your friend how to calculate for cosine.

 

[jd5521]

When calculating your scope height did you calculate it from top of receiver or center of bore? This may have been asked already...