.300 Win 200 grain, Ballistic Charts not adding up please help.

[Ahugemuledeer]

Hello out there,

I’m seeking help with establishing some ballistic Data that has me scratching my head.

Gun is a .300 win mag tikka T3x Lite stainless (24 inch) barrel. Ammo is Federal Terminal Ascent 200 Grain. Scope is a Leopold VH 5, 3-15 X. Zero @ 100 yards, sight height 1.75 inches, altitude Aprox 4000 ft.

Shoots very good, consistent accurate groups out to 500 yards (furthest tested). However, the ballistics Charts are not even close to accurate, on the box or on any other app I’ve used and I don’t understand why. Federal Claims 2810 FPS muzzle velocity, however I do not have access to a chronograph at this time.

For example, @ 500 yards all charts call for -49.6 inches of drop. I have tested this over and over, and what I am actually getting is -38 inches of drop at 500 yards. The gun is in-fact zero at 100 yards.

Can someone help explain this, and also explain how to make a ballstic chart correspond, as my next goal for the set up is 700 yards.

According to my dicking around with Balsitics calculators, I need a muzzle Velocity of 3050 FPS to make this make sense, which would be 240 fps faster than Federal claims.

Is this even possible? Can I use the 3050 fps input and assume accurate data for 600, 700 yards?

Hoping someone has some ideas.

 

[TNKnoxville]

What elevation are you using in the calcs and what elavation are you shooting at? I have the same gun in a Roughtech shooting the TA and so far using the Hornady calculator everything looks good.

 

[TNKnoxville]

My sons shoot the TA's in 7 mm mags and they are both spot on to 660 yards using the Hornady calcs.

 

[Gstew1930]

Put that velocity in your calculator at shoot to 700 & you should know

 

[SDHNTR]

1. Stop using inches, ever.
2. True your drop at 700, plug in the corresponding velocity.
3. Be sure you have BC and atmospherics properly accounted for.
4. Check zero. Be sure it’s dead nuts.
5. Try again.

 

[ChrisAU]

How good is your 100 yard zero?

 

[AZ_Hunter]

Without a chronograph you are missing a very important piece of data. Your true muzzle velocity, environmental conditions, actual BC, etc etc will all have an impact on your dope. Going off box data just isn’t going to cut it.

Air density dramatically changes the dynamics of bullet flight over distance.

 

[Wrench]

I've calculated mv based on impacts and come out as close to perfect as can be measured.

You need to zero at one spot and measure your actual drops at exact known distances and extrapolate backwards. It sounds much more difficult than it is.

 

[wind gypsy]

Hello out there,

I’m seeking help with establishing some ballistic Data that has me scratching my head.

Gun is a .300 win mag tikka T3x Lite stainless (24 inch) barrel. Ammo is Federal Terminal Ascent 200 Grain. Scope is a Leopold VH 5, 3-15 X. Zero @ 100 yards, sight height 1.75 inches, altitude Aprox 4000 ft.

Shoots very good, consistent accurate groups out to 500 yards (furthest tested). However, the ballistics Charts are not even close to accurate, on the box or on any other app I’ve used and I don’t understand why. Federal Claims 2810 FPS muzzle velocity, however I do not have access to a chronograph at this time.

For example, @ 500 yards all charts call for -49.6 inches of drop. I have tested this over and over, and what I am actually getting is -38 inches of drop at 500 yards. The gun is in-fact zero at 100 yards.

Can someone help explain this, and also explain how to make a ballstic chart correspond, as my next goal for the set up is 700 yards.

According to my dicking around with Balsitics calculators, I need a muzzle Velocity of 3050 FPS to make this make sense, which would be 240 fps faster than Federal claims.

Is this even possible? Can I use the 3050 fps input and assume accurate data for 600, 700 yards?

Hoping someone has some ideas.

How many shots and how large were your groups at 100?

How did you validate drop at 500 yards? Did you leave your scope at it's 100 yard zero and measure drop? How many shoots were in your group and how large was the group at 500 yards?

There's a lot of opportunities for error here. Error in zero, error in scope function, shift in zero between shooting 100 and 500 yards, possible up drafts when shooting at 500, etc.

An error in zero and an error in velocity could account for that.

That bullet could be loaded to 3050 fps in a 24" WM but I'd be shocked if factory ammo is doing that.

 

[northernalpine]

@Ahugemuledeer some additional questions:

Did you zero your turret after zeroing your rifle?
What ballistic calculator are you using?
Are you inputting G1 or G7 values?
Where are you pulling atmospheric/environmental data from?

Getting 3000+ fps out of a 24.3” Tikka barrel with factory Federal 200gr rounds is unusual but not unheard with 300WM. I imagine your actual MV is closer to 2860-2900.