You are kind of off the reservation here.
0.355" projectiles are normally used for 9mm & 357sig.
38 S&W is an ancient very low pressure cartridge designed around a 0.361" projectile.
How it will behave if you try to cram a slightly undersized but all copper projectile down its gullet is anyone's guess.
Have you slugged your barrel to see what size it is?
What is your goal here?