Its the convergence. Few years back gunning in bombers was like shooting lazer beams. Something changed and I brought it up. Never really tried to figure it out until tonight. The convergence is shorter. I used to be able to accurately pop planes 1k out. Now im lucky to hit within 600. No complaints just stating observation. 
No, I think your out of practice. hen I was in on you last night, I got closer than norm when fighting you. Your SA was horrible compared to how you use to fly, and by getting that much closer I took you down before you could get a bead on me.
I think if you play a bit more you'll find that the guns are the same and you'll be knocking everyone out of the sky again with ease.