Don't really need mag. loads. I think you are telling me to use .357 brass and one of those powders, use the .38 data in the book , and up the powder 10%. I, have never loaded that way because of saftey reasons.If i an not sure of what I am doing I do not do it. No, I really do not need high power .357 loads. what if I would go down it bullet grs. say like 125 grs. But, according to the book for 125 grs. useing H110 that load starts at 17.4. Would that b a lighter load? It seems the heaver bullit the less powder. I either heard or read some where by using a lighter bullet can erode you gun, because of the smaller bullet. I, do not see how this could happen because of the AOL.
If you do not want magnum loads, W296 or H110 are not good powders. They cause problems if you reduce the load below published minimums.
2400 or IMR4227 are a bit more flexible in that regard, but still, if you do not want magnum loads there are a lot of better powders for light loads.
Also, for plinking or just range use, Hornady XTP bullets are a bit pricey. Cast, swaged, or plated are more economical and work great at 38 Special velocities. But, it is your choice.
HP38, Winchester 231, Unique, Accurate #5, and many others are great for light 357 Magnum loads or 38 Special loads.
You can safely shoot 38 Special ammunition in your 357 Magnum gun. The reason folks use 357 Magnum cases even when loading light ammunition is to prevent a build up of carbon at the front of the chamber that can occur when shooting the shorter 38 Special cases. If the carbon ring is not cleaned out every once in a while, it becomes difficult to chamber the longer 357 Magnum cases.
In my opinion, most authors of loading data figure folks that load 357 Magnum want magnum level loads so their data tends to that direction. As a result, minimum 357 Magnum loads are usually higher than maximum 38 Special loads.
So, 38 Special loads can be used in 357 Magnum cases although minimum 38 Special loads in a 357 Magnum case could reduce the velocity of the bullet too much that the bullet gets stuck in the barrel. So adding 10% to a 38 Special load in a 357 Magnum case should raise the velocity to match the 38 Special load in a 38 Special case.
In loading this way, I'd stay away from powders considered magnum handgun powders.
Shooting light weight bullets do not erode your barrel, shooting light weight bullets at magnum velocities with lots of powder might. Generally, it is the heat, velocity, and the longer time at higher pressures that does the damage.
There is nothing wrong with being conservative and cautious when it comes to reloading.
Hope this helps.