I wouldn't feed a J Frame a steady diet of +P's but if you were carrying one (in the US for example) with +P and practising with standard velocity, you should be fine. Lots of folks in the US have been doing that for years. A steady diet of +P's would sour you on those little revolvers quite quickly - mine used to give me numbness in the shooting hand after 300 rounds, it was a J Frame 357.