Thread: What are you using for pressure estimation in your handloads.

Greetings all,
Raining again in HB today so here is some more on my normal load development.
For various reasons I may need to do some load development for a 7mm-08 soon so have used this as an example. The rifle is a loaner so lets say I have no loading history for it. I have plenty of AR2206H, 145 grain Speer projectiles and the rifle is to be used for mid range target shooting. Hodgdon lists a max of 41 grains of H4895 (AR2206H) for 2,728 fps with this projectile so a start load of 39 grains is selected, a little above the Hodgdons start load. Previous testing with this powder lot has show it close to the data in my .308. The relationship of powder charge to both velocity and pressure is quite linear and the expected velocity for my initial load works out to 2,625 fps in a 24" barrel which is what the rifle has. A shorter barrel length could be adjusted for using a loss of 25 fps per inch down to an 18 inch barrel and more below that.
Next the load will be chronographed using my Oehler 35P and the result used to calculate the load needed to achieve the Hodgdon max velocity to validate the Hodgden data. The max could then be worked up to in a couple of steps.
For cartridges that are loaded to lower pressures like the 6.5x55 I would calculate the target velocity using the John Barsness Rules that I have posted and written about previously. The point here is that I work up to a maximum velocity rather than a maximum powder charge. More later.
Regards Grandpamac.