A chronograph is the only way to know for sure. While I am a big fan of the 260, I have heard not so good stuff about the 260 with short barrels. Proper bullet choice might help but I have read quite a few credable reports of poor bullet performance because of lack of velocity. It might help to drop down to the 100 grain Partition. The best thing I have read comes from the performance of the ballistic tip however. I think a 24 inch barrel would serve the 260 much better. IMO