Ok, I know how to BZO an A1 & A2.  Even have a stack of the right targets to do the job.  

Anyways, I now have a Stag M4 with a 1/9 bbl.  
I have to sight in the BUIS, Carry Handle, and Aimpoint.  

My question is, since I plan to shoot various makes & weights through it, what is the middle ground weight to BZO out of the shorter barrel with this twist.  

Figure that I shoot on the low side at 40gr. and the high side of 69gr.
What is the best weight to do the initial 300m BZO.  

Normally, I BZO all my weapons with Mil-Spec ball and weight, 230 in .45, 115 in 9mm, and 55 in 5.56 in my original SP-1.  This is my normal plinkin ammo too.  And Im pretty much leaning towards the same here.  

But I figured Id ask here first, see if anyone had any different thoughts.  

Definitely M193 (55 gr).  

Sight in what ever you plan on keeping loaded in your mags for self defence. Make notes on ajustments necessary for other ammo you may use later. There's a lot more at play in POI than just bullet weight.