JimL, If you read almost any reloading manual they will state if you change one component of the described load you need to back off & start with a lower powder charge. Even different brands of the same weight bullet can give different pressure. Different primers can too. I'd suggest purchasing a couple of good loading manuals, & read them thoroughly to get started on a safe career of reloading. Done correctly, reloading is satisifying,safe,cheaper than factory, & you can tailor a load for a specific gun. Good Shooting. Frank