I have a ballistics question about the .300 AAC Blackout

[jame]

I have my AR set up to shoot the .300 Blackout, and I'm zeroed at 1" high at about 30 yards using S&B 200 gr. subsonic rounds.

If I were to switch to a 150 or even 125 grain load, how would that change my zero at 30 yards?  At 100?

[Cougar_ml]

S&B 200 grain subsonic does 1060fps

the 147 S&B does 2076fps

the 124 S&B does 2165fps

 

so I have no idea how to figure out exactly how your zero will change, but I checked with an online ballistics chart and used a zero of 0 yards and sight elevation of 0 yards, to just compare bullet trajectory from the muzzle.

 

200

http://www.shooterscalculator.com/ballistic-trajectory-chart.php?t=b997e56e

 

147

http://www.shooterscalculator.com/ballistic-trajectory-chart.php?t=702d2abb

 

124

http://www.shooterscalculator.com/ballistic-trajectory-chart.php?t=aea076c0

 

at 30 yards it shows the 200gr subsonic being a little over 1 inch lower than either of the supers, which are close enough not to matter.

at 100 yards the 200 has dropped over 16 inches, where the other two are right around 4 inch and 4.3 inches of drop, so 12 inches more drop with the subsonic round than the supersonic rounds.

at 300 you are talking 41 and 44.5 inches of drop on the two supersonics, so still pretty close, compared to 156 inches with the subsonic, so more than 110 more inches of drop.  

Every gun is a little different, but I think this gives you a broad idea of what to expect.

[Cougar_ml]

*sigh* I don't even have a 300BO gun (yet), but it at least gives me an idea of what to expect if I ever do.

[AK_Stick]

What’s more of an issue, is depending on the bullet, they may not group in the same plane of elevation. 

 

My gf’s 300 (Ruger Ranch) will shoot the Barnes TSX into very pretty little groups. But it does so about an inch to an inch and a half left of the of the 200 grain subs.