I have a 340M&P that I carry all the time. I also carry a 640 both loaded with 38 spl+p loads. The 340 is more exhilarating to shoot, but the 640 is a *****cat. Either way, they have the same feel (same grips) same sights, and "feel" the same so practice with either works.
Sounds like you need a steel J frame ��