Avenge X tuning

[Mrredhead]

Hello
Just got my new Avenge X .22 rifle its one of my first pcps and I was wondering if anyone had already tried a good slug tune?

I tuned mine to shoot 21 grain javelines at 980 fps and I get about an 1 group at 65 yards, would anyone know an estimate of what speeds I could achieve with 25 grain jts at this setup?

 I would like to use them for target shooting since they're less expensive but I need the power of the slugs for the hunting I do