My first choice for a heavier cartridge is my SA M1A. It's relatively heavy but accurate and powerful. If you're looking at lighter cartridges, an AK with a folding stock and 922r compliant parts is a good option. Cheap and readily available ammo. Reliable.

As an AR alternative in 5.56 I chose a mildly customized Mini14. Traditional stock, high cap, cheap to feed, i can hit what i want with it. I'm happy with it.

Of course, I'm not sure why an AR wouldn't be your first choice given the aftermarket options and well sorted out functional reliability.

Is life so dear, or peace so sweet, as to be purchased at the price of chains and slavery? Forbid it Almighty God! I know not what course others may take, but as for me, give me liberty of give me death! P. Henry

Deus vult!

Rhodesians all now