I believe GKs were designed primarily as accurate, longer range loads, where terminal velocities would be fairly moderate.
The most accurate handloads I've found for my .338 WM were both thrown together "junk loads" to get rid of some bullets I didn't want. The Sierra GKs run right at 1" groups at 200 yards. I wrote that load down....
The one round of same I used broadside on a yearling moose at 160 yards performed adequately.. But he was already on his last legs (3 of them to be exact....
) The bullet exited and was not recovered, the entrance and exit holes and wound channel were acceptable and not remarkable either way. He died without much meat damage from any of the rounds. The hand-load GK was the 4th shot fired, and showed a somewhat larger wound channel than the previous 3 Trophy Bonded Premium factory rounds, fired at different angles ( the 2nd took out his knee- oops). The two (first and third) TB and fourth GK rounds exit wounds could be covered by the palm of my hand. In fact, I've got the off-side shoulder blade with bullet holes on the piano downstairs - a "trophy" of the yearling kill, made under difficult shooting conditions.
I didn't want those 30 GKs bullets that came with the used rifle because of their frangible rep... so junk loaded em and shot most of them up as test ammo with customer guns before I checked accuracy. I still have 3...
The other junk-load turned keeper is Hornady 250 RN. Ugly, Ugly, Ugly. Also thrown together with no work up, just to get rid of the ugly damned things. 5 at a hundred go inside 1", and are zeroed 2 inches high at that range. My average moose shot is about 60 yards for the 20 bulls I've killed. The longest two have been about 160 -- Those RN will do fine within 250 yards.
Wrote that one down too...
I'll probably die before I use those up- I've over 100 of the damned ugly things, and my perfect moose season sees 3 shots fired - one to check zero pre hunt, one to drop moose, one insurance shot on walk-up (Bastids have scared the crap out of me thrice over the years- an extra round spent at 5 yards is well worth it!!!)
The nice thing is that the 3 remaining GKs that I have print 3 inches higher at 100 yards than the Hornady RN. My average moose shot is about 60 yards- but the GKs are my 500 yard insurance rounds.....
I have no qualms about their performance at that range.
My understanding is that GKs terminally perform best at somewhat modest velocities, at whatever the range may be. Load 'em down for short, or up for long, or live with the in-between..
I've changed my opinion of GKs based on experience vs "read-about". I would not hesitate to use them in any situation where plain-janes are appropriate at modest velocities. If terminal velocities (at whatever range) is under 2800 or so, I think they will do fine.
However, I'd not pick them to shoot much of anything at 50 yards with a 7 Mag. for example.
