Strange Ballistics

[elkhunter100]

Powder: 72gr of IMR 4831
Bullet: 210 Partition
Brass: Winchester
Primer: Winchester Magnum Rifle
Rifle: Browning A-Bolt
Muzzle Velocity: estimated 2700 fps based on load data in Nosler #6
Zero: 200yd
2" high @ 100yd

At 360yd bullet only dropped about 8". Expected about 16-18" based on drop tables in Nosler #6 and multiple online ballistics calculators. I have been trying to find information that might explain the difference.

Does anyone have any ideas?

Thanks for the help.

 

[nvbroncrider]

First higher velocity than what is listed and second your sighted in for over 100 yards. That's the first 2 things I'd look at to verify.

 

[SJB358]

Yeah, I would bet you are closer to 2900 with that load and probably a little higher at 100 yards than 2". I would reverify your 100 zero and then reshoot. Sounds like a great combo though.

 

[elkhunter100]

Thanks for the information. Very good points.

I do not have a chronograph so I only assumed the velocity based only similar loads listed in the Nosler #6.

Yes, it is sighted for 200yd. I did not measure with a scale.

I did run the ballistics calculator again this morning with 2900fps and different zeros from 200 - 250 and it does seem very reasonable.

Again, thanks for the response.