Silhouette competition with Talon SS

I’ll be trying my hand at Silhouette shooting this Sunday. I’ve put in some practice time with my Tallon SS, and (hopefully) I’ll be able to hit a few of those little metal critters. I need a better scope, but I can’t swing one right now. I was thinking that I might equip my SS with a 24″ barrel in .177 for Silhouette. Does the .177 offer any significant improvement in ballistic coefficientcy, or are the .22’s and the .177’s about the same? I’d like to get my rifle shooting as flat as possible because this would make for less elevation changes or hold-over. Will the .177’s take out the Silhouette targets reliably? I’d love to hear from anybody who has put their Air Force rifle to Silhouette use.
DougT