250 gr Berger Elite Hunter ballistic coefficients

[Rhovee]

I wouldn't be adjusting my BC at 300 yards. Pretty much all my rifles end up 3-3.5 moa at 300. From a 6 creed to 338 edge.

 

[338 dude]

Thanks for your input, guys, I really appreciate it. I have never used multi bc before, so I will look into that. I appreciate the photo of Litz' info as well. Sorry but I don't know how to convert time of flight for BC is either here's a picture of the page in Shooter my ballistic app I don't know about others but Shooter will let you add multiple BC's it's basically like your own custom curve model

So what adjusted BCs do you guys get with your velocities and twist rates? Bill, I see you TOF data, but I don't know how to convert it.

 

[skipglo]

Hey all,
I did a fair amount of searching, and couldn't find a discussion of this. Sorry if I missed it!

Berger lists the g7 BC of the .338 250gr Elite Hunter as .351. I am sending it out of my 338 Sherman Short Mag at 2750 (measured on a LabRadar), 11" twist. I am using Strelok Pro for dope calculations, and that's where my problems started. I sighted in at 100, but when I took it out to 300 (farthest length available at my range), the POI was lower than I expected. Using the BCs published by Berger, I was hitting lower than I should have been. When I adjusted the BC to match performance, Strelok calculated it at .322. Today, I extended it out to 560 and 688 yards. The dope yielded by using a .322 BC was spot on at both distances.

Is that to be expected (because of my lower velocities)? Or are there other factors that I should consider?

There are dozens of factors affecting bullet performance and you knew enough how to correct for it with STRELOK. That's what I like so much about it. Once you give STRELOK the right info ... good to go...no point in looking for more Goblins... you did the right fix

 

[adam]

Twist rate and velocity affect bc. Take a look at the longer technical sheet of bc on the Hornady site for their eld- eldm. Not the same bullet, but a similar profile and weight. It illustrates the conditions nicely.

I shoot berger 180vld and vldh in my 9 twist magnum. At 2950 my .675 bc matches really well out as far as I can shoot.... even seemed on at a mile.

the conversation I had with the hornady rep helped me understand that if I could get the same velocity in a 1-7.5 or 1-8 I would get much closer to the .818 hornady lists for the 180 eldm... in that weight I believe the two bullets are very similar.

 

[El Matavenados]

Thanks again, guys. My first inclination was that I should adjust my velocity, but I really want to believe that my LabRadar is accurate. I need to get the old chronograph out and double check the numbers. I don't remember the specific numbers, but when I used Strelok to calibrate the velocity to the drop I was getting, it was a quite a difference.

This is all part of the learning curve for me, and I appreciate you helping flatten it out a bit! I will keep working, applying the suggestions that have been offered, and ultimately, find a setting that works and call it "good enough"!

 

[dfanonymous]

You shouldn't be adjusting bc at that 300 yards in. It's mv or scope tracking. There's more to keeping a constant muzzle velocity then just running it through the chrono and calling it good.