Hornady BC

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CAC

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Hi,

I have a question around Hornady's BC numbers. I know they have be using doppler radar for the new ELD bullets, but is this what they use for all of their bullets? I only ask because I have a .308 150 gr GMX and a .308 180gr SST that look quite similar, but the 150 is .415 BC and the 180 is .480.

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Of course looking at a bullet wont give you the whole story, but they market the 150 SST and Interbond to have a .415 BC as well. I think it is a marketing ploy to make people think they can just swap bullets and go shoot, but that may be the cynic in me.

What are your thoughts?

Thanks,

Chris
 
As far as I'm concerned BCs published by manufacturers is all marketing mumbo jumbo. They might be useful for comparing bullets from the same company, but company to company is a total sh!tshow.

As for your specific question, i have trouble believing a soft nose interbond has the exact same BC as a tipped SST. I call bullshyte.

Heavier bullets of similar design tend to have better BCs so i would expect a 180 sst to have better bc than a 150 sst.
 
Suther said:
As far as I'm concerned BCs published by manufacturers is all marketing mumbo jumbo. They might be useful for comparing bullets from the same company, but company to company is a total sh!tshow.

As for your specific question, i have trouble believing a soft nose interbond has the exact same BC as a tipped SST. I call bullshyte.

Heavier bullets of similar design tend to have better BCs so i would expect a 180 sst to have better bc than a 150 sst.
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I'm relying on manufacturer's BC information to calculate come-ups and wind drift for long range shooting. If they were "marketing hype" I would be in trouble. But fortunately I'm pretty close in real life conditions. So, I know that they provide correct BC information for each bullet. BC is determined by bullet length, ogive shape, boat tail dimensions and other minor factors such as cannelure.
 
Suther said:
soft nose interbond has the exact same BC as a tipped SST
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I think you're confusing the Interlock SP with the Interbond which has a polymer tip like the SST

On the other hand trusting an advertised BC past 400yds is not a good idea. You need to shoot and record your drops.

Here's a research paper(that mostly uses Brian Litz's testing) on the % difference between advertised and tested BC http://www.dtic.mil/dtic/tr/fulltext/u2/a554683.pdf
 
a heavier bullet of the similar form factor will have a higher BC. The sectional density is higher. The challenge is knowing what ballistic model is used and in general the advertised numbers are more about marketing...
 
wilbar said:
I think you're confusing the Interlock SP with the Interbond which has a polymer tip like the SST

On the other hand trusting an advertised BC past 400yds is not a good idea. You need to shoot and record your drops.

Here's a research paper(that mostly uses Brian Litz's testing) on the % difference between advertised and tested BC http://www.dtic.mil/dtic/tr/fulltext/u2/a554683.pdf
Click to expand...

You are absolutely right I mistook the interbond for the interlock. NOW having the same BC makes a whole lot more sense. lol (I am going to go ahead and blame reading off my phone while I was supposed to be listening to the professor...)

RifleDude said:
I'm relying on manufacturer's BC information to calculate come-ups and wind drift for long range shooting. If they were "marketing hype" I would be in trouble. But fortunately I'm pretty close in real life conditions. So, I know that they provide correct BC information for each bullet. BC is determined by bullet length, ogive shape, boat tail dimensions and other minor factors such as cannelure.
Click to expand...

What sort of ranges??
 
Bullet weight is also what brings your BC number up. Heavier weight usually performance at longer ranges to deflecting wind and maintaining energy is compared to a lighter bullet is better. The sectional density may look visually the same externally but it's the weight and the slight ogive shape, groove bands, and boat tail angle that will change the numbers.
 
CAC said:
Hi,
I think it is a marketing ploy to make people think they can just swap bullets and go shoot, but that may be the cynic in me.

What are your thoughts?

Thanks,

Chris
Click to expand...

Hornady states you can load the gmx to the same specs as a lead and copper bullet. I have done it many a time. So yes you can just swap bullets and go shoot. I load 30-05 with 57gr h4350 with 165gr sst and 165gr gmx. Both shoot excellent and both shoot pretty much same poi.
7mm-08 same deal I shoot 139gr sst and 139gr gmx both same powder charge gmx is a little slower not sure why though but for normal hunting ranges it wouldn't make a lick of difference.
 
RifleDude said:
I'm relying on manufacturer's BC information to calculate come-ups and wind drift for long range shooting. If they were "marketing hype" I would be in trouble. But fortunately I'm pretty close in real life conditions. So, I know that they provide correct BC information for each bullet. BC is determined by bullet length, ogive shape, boat tail dimensions and other minor factors such as cannelure.
Click to expand...

You forgot weight. For a similar shape, the heavier projectile is going to retain velocity better. Thus higher BC.
 
Suputin said:
You forgot weight. For a similar shape, the heavier projectile is going to retain velocity better. Thus higher BC.
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For a given caliber, assuming similar ogive, a heavier bullet is longer and therefore has a higher BC. A heavy blunt nosed bullet in a given caliber has a lower BC than lighter bullet in a given caliber that is longer and has a more "streamlined" shape. For instance, a Hornady .308 155gr AMAX has a BC of 0.435 while a Hornady .308 170gr Interlock FP has a BC of 0.189.
 
somemof giu might have noticed that the bc has changed on the boxes of some bullets.
Apparently they now measure bc at 200 yards,so the new value is slightly higher. The email I got from hornady said that they were measuring bc at 800 yards however the rest of the industry measures the bc at 200 yards,so they've decided to do what the rest of the industry does so it's an apples to apples comparison.
So you might notice on some bullets the advertised bc has increased. Nothing about the bullets have changed. Just the distance they measure it at has.
Just a heads up.
 
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