A MilSurp Enfield (even with great optics) will post 4" groups at 600 or 8" groups at 1000? Unless I'm mistaken (which is possible I'm not an expert on Enfields by any stretch) I think most folks would be thrilled with getting an Enfield to shoot one MOA after a good deal of work; let alone off the shelf.

No argument on the versatility of the cartridge or the Enfield rifle.

FWIW I'm not sure that shooting >600 yards is going to be likely for many of us in a survival situation anyway.
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