I am dumbfounded how you or anyone else can get into reloading and subsequently hand loading and NOT having a chronograph.
It's like being a PC tuner without the ability to measure temperature, or a mechanic working on engines and not having access to the ECU or a dyno.
Following the "book" load is all fine and dandy BUT when you are playing near max loads (and generally that is where the majority of people choose to go), you NEED to know the velocity numbers out of YOUR gun, at YOUR elevation, in YOUR shooting environment.
This is far more critical than going down the rabbit hole of cleaning primer pockets, lol.
And btw, the Chronograph, may just tell you that all of the meticulous case prep work you are doing does not make any difference in the actual results as the powder charge you are at is not in an accuracy node.
Get a chronograph, do a ladder test with your chosen powders and bullets, find the accuracy nodes, load some up, throw them at paper, generally the accuracy node will equate to nice tight groups (due to low extreme spreads and standard deviation), and then go down the rabbit hole to see how much more good prepwork can cut down in group size.
GET or borrow a chronograph.... either a cheap $100 Shooting Chrony/Competition Electronics OR a $500 LabRadar. But without knowing the ACTUAL velocities, you are shooting with half of the information.
If you want to borrow my chrono, you are more than welcome to... just remember, you shot it, you bought it. Or you can come shoot with me and try out my new LabRadar.