i have noticed that when i have worked up loads for my .308 and 30 30 i have found the same weight projectile seems to group best at the same charge.
for example the .308
i have shot 6 diferant projectiles in 150 grain and 3 in 180 grain. loading the case with 46.5 grains of ar2208 gives the best groups in 150 grain and 42.5 with the 180 grains, the best grouping results did vary between the diferent brand projs but the best group for each was still found at the same charge.
i have found the same results with the 30 30 but i have not shot as many diferent types of projs.
i am using the fed 210 primer and ar2208 powder and am very happy with the results i just found it interesting.
anyone noticed the same thing?
greg

I have not found the same thing. Each of my projectiles requires working up with powders and seating deoths to find the sweet spot.

Greghud, Very loosily on the surface I might agree with you. However as soon as you start to load for extreme accuracy and pay lots of attention to the details like distance from the lands and actual bullet diameter and bearing surface... well it's just not that simple. Then again, you are close. Barrel harmonics and charge weight/bullet weight and when the bullet exits the muzzle all come into play here. If you have a good shooting load, then some of the important work is done.