jason41987
member
- Joined
- Apr 10, 2012
- Messages
- 1,293
i know.. everyones thinking.. this topic again?.. well i looked into topics and didnt find much information that was actually new, usually these topics i find were a couple years old and its a rapidly changing market
anyway.. i was looking for a newer, harder hitting upper for an AR15, for longer ranges and looking at all the options i find myself focusing on the 6.8SPC and 6.5 grendel rounds, so i was curious... just how different are these rounds ballistically?
so i found out the maximum length bullets people have been able to chamber in AR15s for these two, 140 grains for the grendel, and 130 for the SPC, then i found matching bullets in these sizes for these cartridges for the sake of eliminating variables and settled on the 6.5mm 140 grain hornady interlock SST boat tail bullet, and the 6.8mm 130 grain hornady interlock SST boat tail bullet and noted their ballistic coefficiencies, .520 for the 6.5, .460 for the 6.8
then in a ballistics calculator i put the coefficiency and weight in, and for the sake of eliminating variables i tuned the velocities of each round to match the same kinetic energy at the muzzle for both of these rounds of 1,900 ft/lbs of energy... ive seen hand loads of this energy to be not all that uncommon for both cartridges, which isnt hard to believe since they had the same case capacities
what ive discovered is at 600 yards, grendel had 793ft/lbs energy and a drop of 118.5" - spc had 710 ft/lbs of energy and 115" drop
at 800 yards grendel had 584ft/lbs of energy and -249" of drop - spc had 503 ft/lbs of energy and 247" of drop
at 1000 yards grendel had 442 ft/lbs of energy and -455" of drop, spc had 374 ft/lbs of energy and and -458" of drop
so what this shows is 6.8 of same energy levels had a very slight advantage at 600 yards, grendel had a slight advantage at a 1000, being a wash at 800
that being said... does this debate really matter? a see grendel guys claim its superior, i see SPC guys state their case, but in the end i cant see enough of a ballistics difference to base any opinion based on that
anyway.. i was looking for a newer, harder hitting upper for an AR15, for longer ranges and looking at all the options i find myself focusing on the 6.8SPC and 6.5 grendel rounds, so i was curious... just how different are these rounds ballistically?
so i found out the maximum length bullets people have been able to chamber in AR15s for these two, 140 grains for the grendel, and 130 for the SPC, then i found matching bullets in these sizes for these cartridges for the sake of eliminating variables and settled on the 6.5mm 140 grain hornady interlock SST boat tail bullet, and the 6.8mm 130 grain hornady interlock SST boat tail bullet and noted their ballistic coefficiencies, .520 for the 6.5, .460 for the 6.8
then in a ballistics calculator i put the coefficiency and weight in, and for the sake of eliminating variables i tuned the velocities of each round to match the same kinetic energy at the muzzle for both of these rounds of 1,900 ft/lbs of energy... ive seen hand loads of this energy to be not all that uncommon for both cartridges, which isnt hard to believe since they had the same case capacities
what ive discovered is at 600 yards, grendel had 793ft/lbs energy and a drop of 118.5" - spc had 710 ft/lbs of energy and 115" drop
at 800 yards grendel had 584ft/lbs of energy and -249" of drop - spc had 503 ft/lbs of energy and 247" of drop
at 1000 yards grendel had 442 ft/lbs of energy and -455" of drop, spc had 374 ft/lbs of energy and and -458" of drop
so what this shows is 6.8 of same energy levels had a very slight advantage at 600 yards, grendel had a slight advantage at a 1000, being a wash at 800
that being said... does this debate really matter? a see grendel guys claim its superior, i see SPC guys state their case, but in the end i cant see enough of a ballistics difference to base any opinion based on that