I agree with you BruceM, what I said or meant to say it's a good starting place. Start there and check the chambering and then you can start to adjust. I have loaded maybe a 1000 rounds working up loads for several rifles, 1 tenth a gr at a time then work on the length. I have chamber gauges that will measure the lands for you. I have comp seating dies, neck turning tool for my rifles. I went all out when I got into it several years back. Some are very touchy on loads, my 220 swift was, and it took a lot of fine tuning to get it down. I had to let all my rifles go, but one 223) due to a devorse but still have all my tools. I never had an semi-automatic but load for several people that shoot the AR-15 and there you have to watch the magazine length. with them I buy the bullets but all my pistols I cast them which is another story.