I have no desire to engage in any argument, but just to add to the discussion from my personal experience...
My PET hunting rifle is a M70 Lightweight in .280.... Killed lots of stuff with it, ranging from woodchucks to a big Alaska bull moose...
Regarding owning rifles with similar/overlapping performance....
I don't own a LOT of rifles, so it makes sense for me to fill performance gaps in my battery when aquiring one...
HENCE, a few years ago I WON a Ruger M77 in .270... It is the only .270 I ever owned... Since I already HAD my .280 and the performance is similar, I never even fired the .270...Swapped it for an XP-100 Pistol in .260, which is something I did NOT have..
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