Question about BC

freebird63 · #1 12-20-2011, 10:30 AM

I am curious about how much of a difference it would take in the BC for you as the shooter to notice? Say if you compare a 7mm 168gr berger with its BC of .617 and say a 7mm 160gr accubond with a BC of .531??
I have a custom 280AI, so far I have shot 140gr accubonds out to 200 yards and 162gr amaxes out to 200 yards also. The 162 amaxes shot very good at 200 yards, 4 shots were all within the circle of a quarter.
Thanks all

winmag · #2 12-20-2011, 11:10 AM

The results are more exaggerated the farther you shoot, especially in wind. At 1-200 yds, you wont likely see much if any difference. However around 600+, the farther out, the higher b.c. shines brighter.

Try shooting both at longer ranges. There's some GREAT places to shoot cross canyon in wind out between Grandview, Mt. Home, & Melba/Nampa. That lil dirt road that goes past the edge of the bombing range, & pops you out at Hells Kitchen. I made it down that short streach in my Jeep, but my knees still shake thinkin about it. There is another way down into Grandview that any normal 4wd can get down, & TONS of places to shoot Looooong range.

Greyfox · #3 12-20-2011, 04:54 PM

With my 6.5x284, not much of a difference under 600 yards. A big difference at long range. At the same velocity of 2970 FPS , 140 Nosler partition with a .490 BC is 1000 FP energy at 750 yards, with a 140 Berger at .612, I get the same energy and velocity at 1000 yards....big difference if you want to shoot a deer at 1000 yards.

freebird63 · #4 12-20-2011, 05:30 PM

Winmag, I have never been over that direction. I use to fish for sturgeon out of my boat off of Cove Arm and it seemed the runway was not far away as we spent more time watching the military jets taking off. I normally go out South of Boise into the military training range and shoot, I have one spot marked off for 1000 yards, when the guys want their play ground back they come out and buzz me with the blackhawks and we know its time to leave. I hope to get some more reloading supplies after the new year and plan on doing more shooting. It seems down around Mountain Home the wind is always blowing. I found a local guy who builds take down steel target stands with 18" AR500 gong. So far I have not got to see my 280AI really shine. At least right now I don't have to worry about rattlesnakes, the last time out and was unloading and set my ammo box right on top of one. Thanx for the info.

budlight · #5 12-20-2011, 10:41 PM

Chuck, It really takes accurate chrono data and ballistic software or charts to see the difference.

Plug in the data for the bc and map it out to say 600 yards. The inches of drop and wind drift tell the story.

If you don't have a chrono just take some reloading book speed and the BC from the bullet in question. You can be talking many feet of difference way out there.