7mm 160 grain Accubond actual BC?

[pharmseller]

My brother is trying to validate his drop at distance using my reloads in his 7mm Rem Mag. He was consistently low (7 shots) 1 MOA at 600 yards. Given Nosler's tendency to overstate BC, how accurate is the published .531 for the 160 NAB?




P

 

[.300winmag]

My guess is about .485-.490 going off of litzs numbers for the other Noslers Litz measured in his book, plug that in your ballistics program and see if the numbers make your come ups match

 

[Ridgerunner665]

I've logged I think about 215 rounds using the 160 AB out to 800 yards...

Out to 600, the Nosler stated .531 is dead on the money...I know Noslers reputation for over estimating BC's well, but the computers got it pretty darn close to right with the 160 AB.

From 600-800 yards, it drops to .513, which is simply the poor G1 drag standard.


All the above is true and range verified for me and my rifle...a 280 Ackley with a muzzle velocity of 3,020 fps.

Here is a 600 yard milk jug hit using the 160 AccuBond...this is cold bore, gun hadn't been fired in months...dialed up 9.25 MOA and hit the jugs dead center, every time.

https://www.youtube.com/watch?v=1W-vZoU1NPA

A common problem is an inaccurate muzzle velocity...if the bullet is slower than he thinks it is, it'll hit lower..for a 1 MOA drop, using the .531 BC, that is around 100 fps.

 

[.300winmag]

Ridge runner is speaking from experience, so I'd go with his advice. If you're using a magneto or lab radar the velocity is in my opinion is good, then check zero and measure sight height as accurately as possible. Also, make sure you're using the correct pressure in your program, that's by far the biggest problem I see people make. Absolute pressure (what a kestrel, iPhone or rangefinder give you) leave altitude at 0, if you're using station pressure (what the weather man gives you), you have to plug in your altitude along with that. Here's food for thought though, these are the two closest bullets to the 160 AB in litzs book I have, from left to right the values are: SD, G7 form factor, G7 BC, G1 BC.

G7 BC is simply (SD/G7 form factor) SD for a 160gr .284 is .283, so .283/1.13 will get you close, then divide that by .512 to convert to a G1 BC and you get the BC range I posted.

 

[pharmseller]

My research indicates that Litz determined the 160 NAB G7 to be .244. What does your math indicate? And where did you get the .512?





P

 

[.300winmag]

.512 is just a conversion factor to get from the G1 BC to the G7, try it on the BC's in the picture, the math I did gives a G7 of .250

 

[kraky1]

Varying twist rates between rifles can make a difference too. If I remember right some of the Litzs own Research exposed that idea quite well. One could even imagine a big difference between an accurate rifle and an amazingly accurate rifle.

 

[Ridgerunner665]

Matching my known dope in the Applied Ballistics app... My drops match up with a G7 BC of .260

 

[SJB358]

Not done to the extent some of you have but I've shot the 160 AB to 600 using Magnetospeed verified Muzzle Velocities and it worked perfect for me at .531. Haven't shot it longer.

I will say I love the 160 AB though. One of the best modern hunting bullets in a fast 7mm.

 

[jezzolo]

I will say I love the 160 AB though. One of the best modern hunting bullets in a fast 7mm.

So what your saying is that instead of me trying to get a load developed using 162gr interlocks, 162gr sst or 160 partitions I should just forget about those and go with a 160gr Accubonds for my 28 nosler?

 

[SJB358]

I will say I love the 160 AB though. One of the best modern hunting bullets in a fast 7mm.

So what your saying is that instead of me trying to get a load developed using 162gr interlocks, 162gr sst or 160 partitions I should just forget about those and go with a 160gr Accubonds for my 28 nosler?

The 160 PT or AccuBond. I'll leave the others you mentioned for hunting. The 160 AccuBond is a great bullet.