jamesh said:
No. We know that the 180 has a higher BC than the 162. What Terry is asking is if the increased velocity you can push the 162 will make up for the difference, it does. It is a total no-brainer that at the same speed the 180 will outperform the 162 in every way.
I am done with this conversation!
Actually, the data I've collected using various Ballistic programs would say otherwise.
The JBM Ballistic Data is as follows:
162 grain at 3005 FPS G1 BC .625 Sights- 1.5 inches
1000y Drop -24.3 MOA Wind Deflection 5.7MOA 90degree 10mph Wind
1500y Drop -50.1 MOA Wind Deflection 10.1 MOA 90 Degree 10 mph Wind
180 grain Match Hybrid 3005 FPS G1 BC .674 1.5 inches
1000y Drop -23.4 MOA Wind Deflection 5.2 MOA 90 Degree 10 mph Wind
1500y Drop -47.0 MOA WInd Deflection 9.1 MOA 90 Degree 10 mph Wind
162 grain 3120 FPS G1 BC .625 Sights 1.5 inches
1000y Drop -22.3 MOA Wind Deflection 5.4 MOA 90 Degree 10 mph Wind
1500y Drop -45.9 MOA Wind Deflection 9.6 MOA 90 Degree 10 MPH Wind
What that says to me given the initial velocity obviously the velocity of the bullet is the key factor... Which is what we would expect to see the lighter bullet exhibiting less drop and as long as it has the extra 115 FPS over the 180grain bullet it will always have less drop than the 180 grain. And of course as suspected the deflection value is always better with the heavier bullet. Pretty much what you would expect. But as you noticed with the muzzle velocities identical at 1500yards the 180 VLD is clearly showing the superior BC with greater retained velocity leading to less drop and deflection in the process. So, then you would go to the range fire test ammo with identical velocities to confirm the BC values by calculating the drop values for a given initial muzzle velocity. Then you after you confirm the true BC's of the bullets (usually done best with RADAR--but you can do it mathematically and if you can create a big enough chronograph you can test for velocities across distance)-- which will then allow you to actually determine just how important the increase in velocity is to the bullet's BC Value. Because if you use G1 BC 's you have to adjust for velocity ranges. I would have preferred to have used a G7 BC number for both bullets. However, Berger is one of the few company's that supplies the G7 Bullet Form BC Numbers...
So, what you can do is once you've actually created a decent baseline information for the bullets and rifle in question using this method-- then you increase the velocities and then you talk about how much of advantage and at what range it will happen for a specific bullet type. Otherwise if you do what you say well I shot bullet x at 100+ FPS faster MV than bullet y with the slower MV but greater stated BC-- it doesn't really give you enough information to claim well if POI's are similar the bullet with the two different bullets the BC's differences aren't that important for specific velocities.. Well, I agree that at 1000yards with either the 162 A-Max or 180 VLD (target match hybrid) the bullets trade off basically the same 1 MOA advantage either in elevation (162 grain advantage) or wind deflection (180 grain advantage area)... So the choice comes down to the shooter does he want to push a lighter bullet faster or heavier bullet slightly slower? For me it is a no-brianer heavier bullet slightly slower with great BC will actually I think pay off in the end better.
But, accurate use of the Scientific Method will always help you out to find the proper solution.