Re: WHAT CABLIER SHOOT FLATER 7MM08 OR 6.5 .284
Redbone,
These are actually quite different rounds. We would need to compare like bullets so lets look at the heavy AMax bullets for both. The 162 gr 7mm is listed with a BC of .625. The 140 gr 6.5mm AMax is listed with a .550 BC.
So as far as BC value goes, the 7mm bullet would have the advantage.
Thats only part of the equation though. Lets look at velocity potential. The 6.5284 will drive the 140 gr AMax to 28002900 fps depending on barrel length on the rifle. Maybe even slightly more with a long barrel.
The 7mm08 will be in the high 2500 to 2600 fps range with the 162 gr AMax or again slighly higher in long barrels.
So as far as velocity goes the 6.5284 has roughly a 100200 to 250 fps velocity advantage with these two bullets.
Now combining the BC for each bullet with the velocity potential for each round let see what they will do. We will take a middle of the road load for each, 2800 fps for the 140 gr 6.5284 and 2600 fps for the 162 gr 7mm08.
Both zeroed at 1000 yards. Lets look at the mid range tajectory, highest point of bullet flight and drop at 1200 yards.
6.5/284
Midrange: +113" @ 550 yards
1200 yard drop: 153"
7mm08
Midrange: +121" @ 550 yards
1200 yard drop: 157"
You can see that the higher initial velocity helps the 6.5284 have a flatter trajectory but cutting 8" off the midrange trajectory. This is really nothing to worry about. Comparing 8" difference in trajectory when we are dealing with 113" to 121" is nothing.
At 1200 yards you can see that the slower, higher BC bullet is catching up to the faster starting 6.5284. At 1200 yards, the 162 gr 7mm08 is actually faster then the 140 gr 6.5284, roughly 1250 fps compared to 1228 fps.
Now as far as "Hitting Harder", well the heavier bullet and larger frontal area of the 7mm08 will win this battle. If we look at the kenetic energy levels of these two rounds we will see that at midrange, 550 yards, the 6.5284 has 1174 ft/lbs compared to the 7mm08 at 1264 ft/lbs.
At 1000 yards, the 6.5 has 616 ft/lbs, the 7mm08 has 716 ft/lbs.
At 1200 yards, the 6.5 has 469 ft/lbs, the 7mm08 has 562.
Basically the 7mm holds a 100 ft/lb advantage over the 6.5284 at most ranges. At longer range this will increase.
One aspect of this comparision that is very important is wind drift.
At midrange, 550 yards they are basically equal in a 10 mph cross wind, 6.5mm has 21" of drift, the 7mm has 20".
At 1000 yards, the higher BC 7mm bullet begins to increase the advantage, 6.5mm has 80" of drift, the 7mm has 75"
At 1200 yards, the 6.5mm has 123" of drift, the 7mm has 114".
So to be totally honest, out to say 700 yards, there is not enough difference between the two to set one apart from the other.
At longer ranges, the 6.5mm will have a slight edge in bullet drop but the 7mm08 has the advantage in energy and wind drift.
Now this is only one comparision and these two rounds are so close that with different bullets or differnet barrel lengths, the results could be slightly reversed, point being, they are very close in performance with VLD bullets.
Good SHooting!!
Kirby Allen(50)
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Kirby Allen(50)
Allen Precision Shooting
Home of the Allen Magnum, Allen Xpress and Allen Tactical Wildcats and the Painkiller Muzzle brakes.
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