I recently struggled with this very same question for my 5.56 SPR. I found a new contender that fit in between weight and length: Mk5 3.8-18 . It ended up being my choice.
NF 2.5-10x42
Length: 11.9 in
Weight: 20.5 oz
NF 4-16x42 ATACR
Length: 12.6 in
Weight: 30 oz
Leupy 3.6-18x44...