Factory Ammo Published Ballistics - True?
 

I've switched to Hornady Custom ammo (162gr BTSP) for my 7mm Mag and found it groups MUCH better in my gun than Remington ammo. However, I've found that the balistics (bullet drop) Hornady publishes for this round are much better than what I'm getting. For example, Hornady says that with a 200yd zero, I should have 6.7 and 19.7 inches of drop at 300 and 400 yds. I'm getting 8-9 and 23-26 inches of drop at those yardages. This is with at 24" barrel, which is what Hornady uses for its tests. Is it normal for ammo manufacturers to "inflate" the ballistics on their ammo or could something else be coming into play?

RE: Factory Ammo Published Ballistics - True?
 

how is your scope mounted, and by that i mean how close to the barrel is the center of the scope, the higer up that center line is the, the worse the problem might be,
now that i think about it, that might actually help, i cant think right now.
also was there much of a headwind?

propmahn
you can never have too many guns

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RE: Factory Ammo Published Ballistics - True?
 

Factories often use pressure guns or other rifles with very tight chamber dimensions to obtain their data. This will cause their muzzle velocity figures to be higher than what most of us get whern we shoot the same ammo in a regular ol' commercial rifle chamber. So, they are not unscrupulously "inflating" their results, but their results are often better than yours and mine!

Keep yore powder dry!!

RE: Factory Ammo Published Ballistics - True?
 

From what I've seen over my chronograph the factory figures are wishful thinking to say the least. A couple of examples, 25-06 ammo rated at 3150 that clocked 2700, 30-30 ammo rated at 2350 that clocked 2025. 270 ammo rated 3150 that did 2800.

Even if your ammo does chronograph at the velocity on the box that's no guarantee the trajectory will be the same. Many more variables come into play with the trajectory. Sometimes a slower load will shoot flatter than a faster load, factory ballistic coefficients are pretty wishful too. The only way to know where a rifle will shoot at a given range is to shoot it at that range.

RE: Factory Ammo Published Ballistics - True?
 

Might also depend on the amount of fouling you have in the barrel as well as your zero range (those sound like a 200 yd zero).

Usually the factory results are faster than real life for whatever the reason. Best bet is to chrono your own and practice at the ranges you want to shoot.