MtnCreek
Member
If he's having it cut to a specific bullet, that won't be a problem.
.300 Win Mag Velocity in 30 inch barrel
- Thread starter LR Sarge
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MtnCreek
Member
Were you plugging conditions to simulate worst case conditions for your area? (In a valley in mid-winter)?
Dthunter
Member
In order to shoot a mile with a 300 Win Mag, you do not need to go with the 230 grain Berger. But they are great for it!
The 210gr VLD does awesome for me! I managed to win an informal competition at a mile a few years ago (20+ Experienced Shooters). I managed to post a 5 round,14" group at a mile. It was a great day indeed!
Using a G1 BC to figure out your trajectory is nearly pointless. The G7 is the standard which a highly profiled bullet trajectory can be predicted much more accurately.
Have fun with it!
The 210gr VLD does awesome for me! I managed to win an informal competition at a mile a few years ago (20+ Experienced Shooters). I managed to post a 5 round,14" group at a mile. It was a great day indeed!
Using a G1 BC to figure out your trajectory is nearly pointless. The G7 is the standard which a highly profiled bullet trajectory can be predicted much more accurately.
Have fun with it!
I used a balmy, sunny day at sea level with the temperature at 70 deg. F.
'Tis interesting that at a mile down range that AMAX bullet leaving at 3060fps has a vertical impact change of about 1 inch for every 10 fps of muzzle velocity. It also drops about 1.3 inches per yard of horizontal range.
And a bit over 2 feet of drift for every mph of cross wind speed. The bullet's maximum height above the line of sight will be about 38 feet at 1100 yards where the wind will be blowing 20 to 40 percent faster than at ground level depending on the terrain.
Ran the same bullet numbers with Sierra Bullets software using a .648 BC and it said the bullet went sub sonic at about 1,500 yards. Sierra's bullets have five different BC's for different velocity bands; BC's for their 30 caliber 210 gr. HPMK range from .530 @ 1400 fps and below to .645 @ 1800 fps and above. I think that AMAX also has different BC's for different velocity bands and .648 may be its highest. Therefore, I believe that unless good BC numbers versus velocity bands are taken into consideration when calculating the bullet's path with any decent degree of accuracy, the numbers you get may well be off quite a bit.
After getting a "shooting boresight" for the sights and muzzle velocities for the loads, I've used Sierra's software with G1 BC standards calculating drop at different ranges up to 1000 yards with all their 30 caliber HPMK bullets shot from two .308 Win. rifles and two 30 caliber magnums. Calculated sight settings versus reality to get zeros at 300, 600, 800 and 1000 yards was within 1/4 MOA. I don't think Berger's software is any better with their G7 BC standard.
'Tis interesting that at a mile down range that AMAX bullet leaving at 3060fps has a vertical impact change of about 1 inch for every 10 fps of muzzle velocity. It also drops about 1.3 inches per yard of horizontal range.
And a bit over 2 feet of drift for every mph of cross wind speed. The bullet's maximum height above the line of sight will be about 38 feet at 1100 yards where the wind will be blowing 20 to 40 percent faster than at ground level depending on the terrain.
Ran the same bullet numbers with Sierra Bullets software using a .648 BC and it said the bullet went sub sonic at about 1,500 yards. Sierra's bullets have five different BC's for different velocity bands; BC's for their 30 caliber 210 gr. HPMK range from .530 @ 1400 fps and below to .645 @ 1800 fps and above. I think that AMAX also has different BC's for different velocity bands and .648 may be its highest. Therefore, I believe that unless good BC numbers versus velocity bands are taken into consideration when calculating the bullet's path with any decent degree of accuracy, the numbers you get may well be off quite a bit.
After getting a "shooting boresight" for the sights and muzzle velocities for the loads, I've used Sierra's software with G1 BC standards calculating drop at different ranges up to 1000 yards with all their 30 caliber HPMK bullets shot from two .308 Win. rifles and two 30 caliber magnums. Calculated sight settings versus reality to get zeros at 300, 600, 800 and 1000 yards was within 1/4 MOA. I don't think Berger's software is any better with their G7 BC standard.
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Dthunter
Member
If you have ever shot much at ranges like 1000 +, you would see immediately a difference when using the G7 standard.
Some reading of Brian litz "Applied Ballistics" would be beneficial.
Some reading of Brian litz "Applied Ballistics" would be beneficial.
Ridgerunner665
Member
Lmao
No, I think I used 70 degrees F at sea level.
Get then use Berger's software and check it out.
http://www.bergerbullets.com/ballistics/
MtnCreek
Member
Thanks for the update from 2013. Haha.
spitballer
Member
Sarge keep us posted - great read! I too went with a PacNor and if it can be done, they can do it! FWIW while building my little .223 range rifle I found that a given twist rate seems to favor a given velocity, but I can't explain why - it may have to do with centrifugal force. It happens that my 30" straight cylinder balances perfectly with lead ballast in the stock (21.0 lbs), but if I were to go longer than 30" for a bigger bullet I'd consider balancing with a taper or barrel fluting or both, if it can be done. Regards to Jay at PacNor and good luck to you!
Centrifugal force of the bullet, or the rifle?
spitballer
Member
As I said, difficult to explain. The same centrifugal force that causes overspun bullets to disintegrate when exiting the barrel? Taking energy away from forward movement to press against the bore...
Sunray
Member
A chronometer is a clock.
IMR 7828 with a 208 A-Max gives 2899 fps(H1000 gives 2869) out of a 24" barrel. Max load that is compressed. Nothing Hodgdon breaks 3,000 with a 208. Accurate's Ramshot Magnum powder is doing it with 200 grains bullets. 3011 fps out of 24" barrel with a 1 in 10 twist.
However, accuracy is far more important than velocity.
IMR 7828 with a 208 A-Max gives 2899 fps(H1000 gives 2869) out of a 24" barrel. Max load that is compressed. Nothing Hodgdon breaks 3,000 with a 208. Accurate's Ramshot Magnum powder is doing it with 200 grains bullets. 3011 fps out of 24" barrel with a 1 in 10 twist.
However, accuracy is far more important than velocity.
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