Daniel - You're correct, the older Charter Arms 38s are not +P rated and I believe the newer ones are not +P rated either, so you should stay away from the higher pressure loads.
If you do not reload, probably the best load you can use in your Charter Arms is the standard pressure 158 gn swc, or swc-hp. This was the standard for many years until the high pressure expanding bullet options became available. There are some non +P hollowpoints available but with the lightweight bullets they use I feel you're not going to get much defensive capability out of that particular load. Go for the 158s and you should be fine. HTH. Mikey.