Nosler trophy grade 160 drops

[jmcarrol]

My buddy's 7stw drops at 570 were way off the shooter app suggestion. The app says around 8moa to hit the target but we had to dial the scope to 11moa to hit it. Velocity from my magneto speed averaged around 3254 with ES of 7 fps. Shooting at 2100 feet of elevation. Anyone know why the drops are so far off. I'm using 1.8 sight height with a 100 yd zero

 

[jmcarrol]

We shot 530 yds and the hit took 9.75 MOA. Seems like something weird is going on to require 11MOA at 570

 

[Lefty7mmstw]

not enough info for an intelligent answer.
What bullet are you using?
Factory ammo... correct? Are you sure the speed is the same with every box? or did you sample one box at the range and try to shoot lr with another box?

More info will help but nos bc's tend to be on the HOT side if you aren't using a very fast twist bbl. so I suspect it is mostly a bc. correction issue.

As far as the 1.25 moa change between 530 and 570.... likely shot angle, lighting, or simple sighting error.

 

[ShootnMathews]

As far as the 1.25 moa change between 530 and 570.... likely shot angle, lighting, or simple sighting error.

Possibly even parallax, and I'd say an overrated BC.

 

[jmcarrol]

Nosler trophy grade. Factory ammo 160 Accubond

 

[Lefty7mmstw]

Possibly even parallax, and I'd say an overrated BC.

yep, possibly also a soldering iron on his bullet tip .....

hornady eld-x is supposed to fix the degrading bc, but you have to actually list an accurate bc to start with, a major feat to some manufacturers who think that fiction is better. Those who use radar instead of an astrologer are more apt to be accurate..... I know Hornady, Sierra, and Berger are using radar to evaluate bc...

 

[jmcarrol]

Barrel twist is 1:9.
Maybe it's parallax.

 

[bobs]

Your MV of 3254 is way higher that what Nosler states for that factory load. Another minor factor is that their BC is overstated. They told me that they measure it at 100 yds.

 

[jmcarrol]

Thank you. That's the avg mv I got for five shots using my magneto speed chrono.
Will check parallax and then drops between 3,4,and 500 yards too.