Help with choice

[zrpilot]

I think I know the answer, but wanted your guy's input.

I am looking for a varmint, paper punching platform. Not interested in putting it together. And of course money isn't found on trees.

Thinking maybe someday down the road buying a lighter upper for a good carry gun for coyotes.... Can one just buy the complete Colt upper to make it into a 6920 or equivalent? Am I going about this ass backwards, should I get the 6920 first, then change the upper to a heavy barreled varmint shooter?

1) Colt HBAR Elite approx - $1300
2) RRA LAR-15 Varmint A4 - $1135

Or what else?

Thanks in advance