Tikka 50-100 FPS difference - Bullet Drop Impact

[98TJ10]

In reviewing ballistic charts it seems that even a ~50-100fps difference in (factory) velocity from the printed specs would have a serious change in bullet drop even at 300 yards.. I have a Tikka in 6.5CM, is the only "correct" way to get the true FPS is get a chrono and see what it puts out? I won't be shooting more than 400yds but was surprised when I started playing around with velocity...yes quite the amateur.

6.5 Factory rounds in question:
143 ELD-x
129 American Whitetail

 

[wind gypsy]

Known velocity makes it easy to get out and shoot a long ways and be real close. @ inside 400 yards you'd be best served by just shooting and validating actual drops.

 

[30338]

I just plugged in my 140 berger info and a 100 fps difference is 1.3" more drop at 300 yards. I don't really worry about velocity much. Figure out what speed you have and per above post, go shooting.

 

[TxLite]

Take it out to 300 yards with the approximate velocity and validate it based on the drops. Then verify it out further and make sure the math still lines up.

 

[atmat]

is the only "correct" way to get the true FPS is get a chrono and see what it puts out?

It’s the correct way to get a true muzzle velocity if you shoot over one enough.

But you still need to true your overall system, regardless of whether you chrono or not. That involves zeroing at 100, using a calculator to get close to bullseye at as far a distance you can shoot (ideally near transonic), then adjust your velocity in the app to match the drop you’re seeing. Many guys don’t even bother chronoing anymore.

Inside of 400 the margin for error increases, and you could probably get by with a chrono and not trueing — but I wouldn’t recommend it.

 

[Lawnboi]

Different lots alone of that Hornady can vary more than 50fps in the same rifle.

A chronograph can make it easy but at that range it’s not hard in decent conditions to just validate off box value.

If you think you need to true at 400 yards with known bullets and an accurate velocity I would seriously look at your equipment/shooting ability.

 

[Tahoe1305]

Box velocity hardly ever accurate. A lot of assumptions in where that velocity came from (barrel length, temp, rifle, twist, etc).

To answer chrono and/or shooting at range and back calculating the velocity (need to know/trust BC though) are the only way to verify.

Tikkas typically shoot slower than listed.