11-05-2018, 05:16 PM
We used Hornady's stated BCs for the 123gr SST for the effective range charts. That BC seems to be a bit overstated at .510 G1, and .462 G1 is more accurate from all I've been able to gather.
Same for the 123gr AMAX, which ended up at .468 G1, which I've used to 1000yds and had elevation about dead-on.
On the other hand, their stated BC for the 129gr SST ended up being understated, with Bryan Litz showing .495 G1 vs Hornady's .485 figure.
There is also manufacturing variance to the ogives on bullets, though it has gotten more consistent with modern production methods, so you can see fluctuation of BC values based on lot # and samples within a lot as well.
For those of you who are hunting within 250yds, none of this really matters. The BC values are something those who will be pushing the edge pay attention to more, and in those cases where a majority of shots will be farther, it might have an influence on what bullet you pick.
Even with an 11-12" Grendel in the cold with some of the lower MV readings I've seen people have in the 2250fps range, you're still looking at expansion past 250yds, with over 900ft-lbs.
With a 16" barrel and 2420fps mv with the 123gr SST, you get 350yds expansion, with over 900ft-lbs of energy.
We've been talking about an update for the manufacturers, but since the manufacturing industry fluctuates so much, I wonder if a separate card with manufacturer's list would be a better approach.
Same for the 123gr AMAX, which ended up at .468 G1, which I've used to 1000yds and had elevation about dead-on.
On the other hand, their stated BC for the 129gr SST ended up being understated, with Bryan Litz showing .495 G1 vs Hornady's .485 figure.
There is also manufacturing variance to the ogives on bullets, though it has gotten more consistent with modern production methods, so you can see fluctuation of BC values based on lot # and samples within a lot as well.
For those of you who are hunting within 250yds, none of this really matters. The BC values are something those who will be pushing the edge pay attention to more, and in those cases where a majority of shots will be farther, it might have an influence on what bullet you pick.
Even with an 11-12" Grendel in the cold with some of the lower MV readings I've seen people have in the 2250fps range, you're still looking at expansion past 250yds, with over 900ft-lbs.
With a 16" barrel and 2420fps mv with the 123gr SST, you get 350yds expansion, with over 900ft-lbs of energy.
We've been talking about an update for the manufacturers, but since the manufacturing industry fluctuates so much, I wonder if a separate card with manufacturer's list would be a better approach.
NRA Basic, Pistol, Rifle, Shotgun, RSO
CCW, CQM, DM, Long Range Rifle Instructor
6.5 Grendel Reloading Handbooks & chamber brushes can be found here:
www.AR15buildbox.com
CCW, CQM, DM, Long Range Rifle Instructor
6.5 Grendel Reloading Handbooks & chamber brushes can be found here:
www.AR15buildbox.com