Why are you insistent on trying to turn a sow's ear into a silk purse? The SGK isn't a great game bullet. You've seen core seperation in your own testing. The .358 is certainly not a good cartridge for shooting out to nearly 400 yards. Do you really need to be different that badly?
Get a good tool for the job. A .260, 7-08, or .308 with good bullets will do anything the .358 will do and so much more.
jds,
It's not "just to be different", it's to use what's BEST for me, based on my experiences in the field. That's the .358.
Using the B&C reticle on my .358, I can hit just as consistantly at 375 yards as I can with anything else, which is to say pretty much every time. So it is an equally good tool at that range, compared to a 7-08 (or whatever). I think a .35 caliber, 225-gn bullet at 1800 fps is gonna leave a mark!
As to the Sierra... well... the stubborn person in me just didn't want to think that there could BE a problem with a 225-gn bullet, .35 caliber, on a deer. That's a lot of bullet, and a lightly put-together animal. The core-jacket seperation doesn't really bug me (for deer) but the failure to expand surely does.