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berger.what´s happening?

 
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  #8  
Old 01-12-2009, 08:46 PM
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Re: berger.what´s happening?

DUH,

Here are the projections for the 300 grain bullets:

All of the Berger .338 bullets are designed to be stable in a 1:10" twist, at any reasonable speed (anything over 2200 fps muzzle velocity).

The BC's are based on the dimensions of the bullets, and a database of information I've compiled that relates measured (tested) BC to bullet geometry. This method results in estimates that are typically within +/- 3% of the measured BC.

BC's are given as average values from 3000 to 1500 fps.

300 grain Tangent (non-VLD) ogive:
estimated G1 BC: 0.749 lb/in^2
estimated G7 BC: 0.384 lb/in^2

300 grain Secant (VLD) ogive:
estimated G1 BC: 0.855 lb/in^2
estimated G7 BC: 0.438 lb/in^2

I'm sorry to say that I can't speak for the release date at this time. I think the machine will be ready by this coming summer, but don't quote me on that. Trust me I'm as excited as you guys to give these things a spin!

-Bryan
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  #9  
Old 01-13-2009, 03:08 AM
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Re: berger.what´s happening?

Thanks Bryan.

So I can use my Bergers with the currently published BC´s understanding these are more accurate?? I had read with much interest your articles about the 30 cal 155 g. and 7 mm 168-180 g. Bergers..now I see you put your work to good use

Can you advance any information about the diference between the hunting and the match bullets ( I guess the latter remain the same as they are now in the VLD line).-
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  #10  
Old 01-13-2009, 08:32 AM
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Re: berger.what´s happening?

alg,
The Hunting and Target VLD's are the same on the outside. Same shape, same BC. The Hunting VLD's have thinner jackets to allow for proper expansion, the Target VLD's have thicker jackets since expansion is not an issue for target shooters.
Also in the Target line are some flat bases and Boat-Tails (non-VLD's) but all the hunting bullets are the thin jacketed VLD's.
The 'Match' description still applies to all 3 lines of bullets; Hunting, Target and Varmint, meaning they're all made on the same machines to the same Match tolerances. In other words, our Hunting bullets don't get less attention to consistency/precision then the Target bullets.

Quote:
So I can use my Bergers with the currently published BC´s understanding these are more accurate??
That's correct. Some people were nervous about the BC's changing because the old BC's were so accurate. The new BC's haven't changed very much, usually less than 5% for most cases, and they're even more accurate than before. To put it in perspective, a 5% change in BC will cause just about 1 MOA difference in predicted drop at 1000 yards.
Use the new BC's and shoot with confidence.

-Bryan
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  #11  
Old 01-13-2009, 01:11 PM
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Re: berger.what´s happening?

Quote:
Originally Posted by bsl135 View Post
DUH,

Here are the projections for the 300 grain bullets:

All of the Berger .338 bullets are designed to be stable in a 1:10" twist, at any reasonable speed (anything over 2200 fps muzzle velocity).

The BC's are based on the dimensions of the bullets, and a database of information I've compiled that relates measured (tested) BC to bullet geometry. This method results in estimates that are typically within +/- 3% of the measured BC.

BC's are given as average values from 3000 to 1500 fps.

300 grain Tangent (non-VLD) ogive:
estimated G1 BC: 0.749 lb/in^2
estimated G7 BC: 0.384 lb/in^2

300 grain Secant (VLD) ogive:
estimated G1 BC: 0.855 lb/in^2
estimated G7 BC: 0.438 lb/in^2

I'm sorry to say that I can't speak for the release date at this time. I think the machine will be ready by this coming summer, but don't quote me on that. Trust me I'm as excited as you guys to give these things a spin!

-Bryan
Bryan, could you give us predicted bc's for the 250's?
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  #12  
Old 01-13-2009, 01:58 PM
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Re: berger.what´s happening?

For the 250's:

BC's are given as average values from 3000 to 1500 fps.
250 grain Tangent (non-VLD) ogive:
estimated G1 BC: 0.624 lb/in^2
estimated G7 BC: 0.320 lb/in^2

250 grain Secant (VLD) ogive:
estimated G1 BC: 0.713 lb/in^2
estimated G7 BC: 0.365 lb/in^2

Here's a trick you can use to estimate the BC of bullets that have similar shape but different weight. Just multiply the BC of the known bullet by the ratio of weights. For example, the G7 BC of the 300 grain VLD is 0.438. To estimate the BC of a 250 grain bullet that shares the same shape: 0.438*(250/300) = 0.365.

As another example, consider the 6.5mm 130 grain VLD with a G1 BC of 0.552. Since the shape of the 140 grain VLD is similar to the 130 grain VLD: 0.552*(140/130) = 0.595. In fact the measured BC of the 140 grain VLD is 0.595. I chose this example because it happens to work perfectly. The estimate isn't always exact, but can give you a good basic guess.

-Bryan
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  #13  
Old 01-13-2009, 03:20 PM
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Re: berger.what´s happening?

Have you guys ever considered pre-pointing your bullets with a pointing die? Would raise the BC and keep it more consistent.
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  #14  
Old 01-13-2009, 03:47 PM
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Re: berger.what´s happening?

Tyler,
The benefits of pointing are very real. Unfortunately, so are the manufacturing challenges. I can't speak with authority on the bullet making process, but I think that adding the step of pointing would add significantly to the time and cost associated with producing bullets. The extra cost would have to be passed on to the shooter.
I'm sure the cost analysis has been done in the past at Berger and other bullet makers who choose not to point bullets. Sierra's recent introduction of their new Palma bullet is an exception, but it only applies to the one bullet which is surrounded by many unique influences.
As a shooter, I consider the investment in the pointing die to be very worthwhile, much more so than paying +$2-$3/box for pre-pointed bullets in the long run.
Eric could probably give you a more specific answer based on the realities of Bullet Smithing.
-Bryan
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