Bullet weights for 20" 1/9 AR barrel

[357SigFan]

I'm still on my "quest" for an accurate varmint load. I haven't had many chances to get out and test anything with the AR lately as I've put more effort into getting a load for my BAR ready for deer season. Anyway, I was planning on trying to develop a load using either Nosler or Hornady 55gr BT bullets. What I'm looking for is something "explosive" on varmints such as prarie dogs. However, the Nosler "BT Lead-Free" that was in October's American Rifleman looks interesting. Problem is, at this point, it'll only be available as high as 40gr. Assuming my AR can do the job, is it possible to run a 40gr bullet in a 1/9 twist barrel and achive something around .5 (or less) MOA @ 100 yards?

 

[jpwilly]

Try the 50gr pills. My DPMS with 1-9" bbl likes them the best.

 

[rangerruck]

if doing a factory load, the winchester, big white box, 45 grain varmints. These will be a one hole punch for you, at 100 yds. I have no doubts.