Here is my suggestion,
Burris timberline 4.5-14 power w/ AO. BD reticle..it's cristal clear, and the reticle works good with 40 gr. Standard velocity ammo..I love this scope and found it for 235$ ..shop around you can find a good price..235$ is the lowest price I've seen .
The scope is not big and is right at home on the M&P AR-22 ..