LWRC 6.8 mm vs. POF P-415 .308 vs. Barrett Rec7?
I like the idea and theory behind the 6.8mm... however, you may want to consider availability of ammo when choosing. .308 is going to more available than 6.8mm SPC. For my SHTF rifle, I went with the time and battle proven Kalashnikov. Plenty of 7.62x39mm available. Plus an AK can be had for well under $1,000.
I have to second Glockster20's recommendation.
I also have a AK for my SHTF. A well proven design and ammo is still plentiful
Although I have a M-14 (M-1A) and M-1, etc., etc. My grab and go is the AK.
I would agree with the 308. Proven round and availability at least for now better.
By faith Noah,being warned of God of things not seen as yet, moved with fear,prepared an ark to the saving of his house;by the which he condemned the world,and became heir of the righteousness which is by faith Heb.11:7