09-05-2020, 05:18 PM
I did some more searching and found a couple of more recent posts. I can't figure out how to create images of the original posts, so I'll give the quotes and then links to the threads.
One problem when quoting a G1 BC is that it is not an accurate representation for a boat tail bullet design. The effective G1 BC for a typical boat-tailed bullet varies with its velocity.
Sierra Bullets for example, will provide multiple G1 BC's to be used in differing velocity regimes. Bryan Litz performed shooting tests with the 123 grain SST and found the effective G1 BC to vary dramatically with velocity.
"Here are Litz' numbers for the 123 SST, which I believe is the same (or at least very close) to the AMAX:
G1
overall .462
below 1500 .406
2000-1500 .432
2500-2000 .467
3000-2500 .491
Above 300 .526"
This quote are from post #6 of a 2015 thread discussing the then-new A-MAX. https://www.65grendel.com/forum/showthre...23-amax-BC
I should note that Hornady is not actually lying, it just posted a G1 BC in a velocity range above that reached by a 6.5 Grendel. It was later determined that the SST and AMAX were not the same shape.
This second quote is the one that I was thinking of when I made my earlier post. It just took a while to find. It was made by LRRPF52 on 07-16-2019:
"123gr SST is more like .463 G1, nowhere near .510 G1."
It can be found at post #8 in this thread: https://www.65grendel.com/forum/showthre...-Perplexed
I don't think that Hornady has recently changed the shape of the 123 SST, but anything is possible.
One problem when quoting a G1 BC is that it is not an accurate representation for a boat tail bullet design. The effective G1 BC for a typical boat-tailed bullet varies with its velocity.
Sierra Bullets for example, will provide multiple G1 BC's to be used in differing velocity regimes. Bryan Litz performed shooting tests with the 123 grain SST and found the effective G1 BC to vary dramatically with velocity.
"Here are Litz' numbers for the 123 SST, which I believe is the same (or at least very close) to the AMAX:
G1
overall .462
below 1500 .406
2000-1500 .432
2500-2000 .467
3000-2500 .491
Above 300 .526"
This quote are from post #6 of a 2015 thread discussing the then-new A-MAX. https://www.65grendel.com/forum/showthre...23-amax-BC
I should note that Hornady is not actually lying, it just posted a G1 BC in a velocity range above that reached by a 6.5 Grendel. It was later determined that the SST and AMAX were not the same shape.
This second quote is the one that I was thinking of when I made my earlier post. It just took a while to find. It was made by LRRPF52 on 07-16-2019:
"123gr SST is more like .463 G1, nowhere near .510 G1."
It can be found at post #8 in this thread: https://www.65grendel.com/forum/showthre...-Perplexed
I don't think that Hornady has recently changed the shape of the 123 SST, but anything is possible.