the 120 does look a lot closer than the 110, sd of .22 is better than the .20 of the 110 but still a significant loss compared to the .25 of the 123 6.5I was following everything said here with a nod… up till the SPC reference where you compared a 110g load to the 123g “G” load. Given a modern SPC II chamber with a 120g SST (or 115g gold dot- what I use)… the ballistics at 300 is basically the same with the SPC or “G” out of 16-20” barrels, respectively.
The SPC may actually have the energy edge by a hair with the 120g, but it’s not worth debating when we have ballistic calculators that continue to show that well past 250 yards… same size bullet in same length barrels stay VERY close to each other. Neither is falling on its face at that distance apples to apples.
Again, not starting an argument here! If you wish to hunt past 500 yards with a Grendel, cool. I want to build one for coyotes for that purpose. But for 300 yards out (deer and pigs in my case), in a 16” barrel, using heavier bullets… flip a coin. They will both be neck and neck factory or reloaded- speed and energy.
On bullets… I never liked the lighter bullets for hunting deer or pigs either. Then when we SPC guys got the 120 SST, lots of pig hunters went to them as they do knock them down good. But they are not a bonded bullet and make a mess. As I EAT my pigs I hunt, I MUCH prefer the Federal Gold Dot 115g which opens up very well (AND holds together extremely well at ANY range, going through bone or flesh making clean kills). Nice mushroomed bullet I usually don’t find (on all but the largest pigs), most go through and leave a good blood trail (I also rarely need to follow).
the 40,000' view of it was for me looking at the spc it was 20th century ballistics still, adequate class 2 game sd and pretty typical sub .5 bc (.37 for the 110) and it launched with less velocity to boot, so why I say The Grendel takes it to a different level is it applies 21st century spec, we have class 3 game sd, .5 or better bc and it also had a bit more powder behind it, it effectively gets another 160 yards range potential while delivering a bullet that goes deeper and carrying more energy, anything with .37 bc falls on it's face or maybe I should have better termed it as '20th century ballistics'? anyway using 95% of rated velocity on the 110 6.8 goes 2422 fps mv (1433 ft/lbs me), 390 yards is 1700 fps with 706 ft/lbs and deer size game penetration potentials with that .2 sd, the 6.5 123 at 95% spec launch is 2451 fps (1641 ft/ls me) and at 550 yards gets to 1700 fps with 790 ft/lbs carrying class 3 game penetration potential with that .25 sd. that to me is 21st century performance levels from similar powder burned, that's another level altogether both in flight and terminally
that's why I was into the 6.8 at first because it came out first commercially but I could not ignore the Grendel's 21st century efficiency and it was inevitable that I would end up there, flexibility goes up, and I didn't discuss wind advantage either...the 6.8 needs 4 moa at 390 yards to fight a 10mph cross wind, the 6.5 needs the same at 550 so wind isn't a thought inside 400 for most shots from a 6.5, just nudge the crosshair into it a couple inches really but better stay on fur as these bullets are pretty dang slippery, it's easy to hold 20th century wind hold habits in your head out there, gotta recalibrate the brain to 21st century wind holds
having said all that, the 120 gr 6.8 would narrow this gap, likely middling between these two examples here but still solid 20th century performance while 21st century performance(efficiency) available, I don't like the tougher construction bullet choices in these little micro burners so the 110 would be my choice in 6.8 and I'm a factory ammo guy so that's what I'll discuss always, but if factory 120 Bt's or eld-m available that's what I'd be using as a 6.8 spc guy to close that gap, I can see why the 120 sst would be popular!, I want the rapid expansion design, the 6.5 gives me that with easy to find factory ammo in the Hornady Black, no reloading necessary to get the peak performance from the cartridge available, I dig that a lot, being able to play peak ballistics with all factory gear AND ammo used to be only for a custom gun(twist) reloader guys, so this is a big deal for a bunch of us who don't take the firearms game that deeply on the gear side, some of us are into way too many other things to also be into that too or just don't want things that aren't off the shelf
inside 300 yards not likely to be able to tell much between a lot of these options, we are discussing 25-30 grains of powder burned and .243-.277" pills from 103-123 gr after all
these are magnums compared to those .223 77gr tmk's lol
one other quick view looking at that is, at 400 yards while the 6.8 is falling on it's face for deer size game...I'll have not a second thought of sending that 123gr 6.5 into a broadside elk or moose, next level