I think Ron is on the right track.
As a centerfire shooter when "I" see split brass on the first firing I never blame the chamber. Its the brass. YMMV JMO disclaimer disclaimer ;D
No doubt chamber size plays a role but ALL brass should be able to handle one firing without cracking even in a sloppy chamber. Does'nt always happen though.
Years back unloaded Winchester brass in 204R would come with some splits right out of the bag. Hornady 204R was known for getting a certain percentage of splits on the second firing.
One thing I've noticed in the pics, both yours and another shooters provided in the link. The roll crimp on split brass is readily visible. That could easily be explained by loss of pressure due to leaking gases. But why do the necks measure the same as unsplit brass?
I would look through some fired unsplit brass and see if you can find some more roll crimps still visible. Thats a clue to brass hardness.
And not to let Savage off the hook. You should comparitivly measure the shoulders of your brass against Kona's.
Yes rimfire headspaces off the rim but if your chamber is cut deeper than need be that could cause undue stretching.
How many other lots of ammo have you tried?
As a centerfire shooter when "I" see split brass on the first firing I never blame the chamber. Its the brass. YMMV JMO disclaimer disclaimer ;D
No doubt chamber size plays a role but ALL brass should be able to handle one firing without cracking even in a sloppy chamber. Does'nt always happen though.
Years back unloaded Winchester brass in 204R would come with some splits right out of the bag. Hornady 204R was known for getting a certain percentage of splits on the second firing.
One thing I've noticed in the pics, both yours and another shooters provided in the link. The roll crimp on split brass is readily visible. That could easily be explained by loss of pressure due to leaking gases. But why do the necks measure the same as unsplit brass?
I would look through some fired unsplit brass and see if you can find some more roll crimps still visible. Thats a clue to brass hardness.
And not to let Savage off the hook. You should comparitivly measure the shoulders of your brass against Kona's.
Yes rimfire headspaces off the rim but if your chamber is cut deeper than need be that could cause undue stretching.
How many other lots of ammo have you tried?
By the way I have a f class Savage in 6.5*284 and 6br and they are tac drivers.
In about 2 weeks I`ll have my new baby! Lol 
I am sooo excited! So much to learn!! You will defiantly be hearing more from me now. 
