It's .25 and I've only been able to shoot 3 rounds out of it. I took it out as soon as I got it and its been raining pretty much nonstop for the past 3 days, so I haven't really had much of a chance to shoot it.
If your barrel doesn’t end up being a good shooter I have a TJ’s .25 in 1-22 twist I would be willing to sale. Try lots of different pellets first though.