The original GS was a double chamber bullet like the Nosler Partition, and discontinued ummm loong time ago.
I've used Hot Cores since the '80's mostly in 270's - bought out a dealer in Lousiana one time at about $2-$3 a box and bought all he had in couple calibers or styles & made the already overloaded Suburban squat - and other under 3000 MV guns and always been satisfied with their On Game performance & decent but not stellar accuracy. IMO They are not a target bullet & don't make that claim.
I used to use 270gr Hot Cores in my 9.3x62 and the CZ could stack them in the same hole 5 at a time if I was doing my part...and a real thumper on game, with little or no meat damage.
Got some 120 gr 6.5's I used to put thru a Swede at max max MV's that were close to Sierra PH's acccuracy wise & a little tougher with nice consistent thru & thru's on WTails .
Found a source for some Fusion's that've been commrcially pulled from factory ammo, or sold in bulk as Blems occasionally and am looking forward to trying them when I burn up what I've got on the shelf.
Remember Aesops Fables outcome of the "Scorpion & and the Frog's" crossing the river when they get to other side
TooTaToo...We have MET the Enemy...and He is US !!... Pogo
Those who fail to learn from History are doomed to repeat it...George Santayana