My opinion of Sierra bullets is that they are usually among the most accurate you can buy and they are quite affordable. However, IMHO, they have fallen behind other companies by not offering a premium bullet with either a bonded core or some other mechanism to control expansion. I harvested 3 big whitetails with the .277" 140gr SBT bullet and was not pleased with the performance from any of them. In 2 of the deer, the jacket very clearly separated and the third deer went nearly 200 yards before it dropped. I would not expect the hollow points to perform better, unless you consider rapid expansion good performance from a big-game bullet.
broom, of your 3 deer you shot with the GK, what were the details? Did you shoot for bone? How far did they go? I've not used the GK's on deer, but my brother and I have shot dozens with the Pro Hunters over the last 15 years or so and had exactly one run. They're a top notch deer bullet.Carry two different loads? Ridiculous. Adjust the distance you shoot based on the bullet you have loaded? That would be very accommodating of the game being hunted.
The Partition penetrates reliably, even when the front core separates completely. This causes dramatic wound channels and an exit wound for easy tracking. The SGK just blows up and if/when the animal runs off 150 yards, you've got a much tougher job finding it.
The Gameking is a target bullet, masquerading as a hunting bullet. It uses a simple, drawn copper jacket; technology that is pushing 100 years of age. Sierra makes some of the best target bullets in the world...the SGK is one of them.
We do agree on one thing: The Accubond is a very well-designed bullet that performs well irrespective of distance or impact velocity. It has an excellent BC and would be just as capable on that 500 yard sheep as the Gameking, but if you happen to peek over the top of a ridge and see one at 50 yards, you aren't going to wonder if the bullet is going to perform.
Obviously everyone has their opinion of a bullet and for every bullet there's someone who say's it sucks. I don't think there's too many bullets designed for big game that won't do the job they're designed for as long as their used within their design parameters. Sierras are no different and are a top notch deer bullet. Most HPBT GameKings are tougher then the SP GameKing, though there are a few exceptions, one being the .257 90 grn HPBT....that's a varmint bullet; the 120 HPBT is a big game bullet. I've been working with the 160 HPBT in my 280 and it is very accurate, though I have not shot anything with it yet.
Deer aren't hard to kill and any GK or PH designed for big game will kill them. Premium bullets aren't really needed for deer except in a few instances, but C & C's are hard to beat. I also think too many get caught up in the marketing that if we don't get 90% + weight retention and a perfectly mushroomed bullet, it's performance is questioned. The fragmenting tends to kill quicker which is why when John Nosler designed the Partition, he designed it to lose some of it's weight. Same with the AB, which was designed to perform in a similar manner. I've read recently about the Bergers being extremely quick deer killers due to penetrating a few inches then expanding in an explosive manner.