Thread: First attempt at reloading. Thoughts please.

Greetings @Blackfern,
You certainly have done your homework. I recently loaded 42.5 grains of AR2208 behind the 140 grain Remington Corelokt which is below max in the Hodgdon data for the 139 grain Hornady Interlock. The BT, Corelokt and Interlock are all soft projectiles so the Hodgdon Data is relevant. The load chronographed 2,710 fps average in a 19 inch barrel so your result of around 2,600 fps looks about right for your 42.5 grain load. My chronograph is a 35P with a 4 foot screen spacing. This validates your chronograph results.
Load data needs care in selection. The ADI data of 42.2 grains for the 140 grain is for a harder projectile and the 43.5 grain max for the 139 grain is more relevant for the BT that you are using.
To me the chronographed velocities you got for the 41.5 grain load look high. With the 7mm-08 you would normally expect around 50 fps more velocity per grain of powder added and your other data supports that. Primer appearance is a very poor (i would say practically useless) indicator of pressure. There is much to learn so will post again later in the day.
Regards Grandpamac.