Whichever shoots the best -

The construction of the bullet may be more important for your application than 55 vs. 65 grain weights...

I'll assume the 65 is a SGK. If so, that is a great coyote bullet but for .223 velocities, I may be more apt to choose a 55 of similar construction for a slightly flatter trajectory within calling ranges.

- Greg

Success is found at the intersection of planning, hard work, and stubbornness.