Originally Posted by JeffVN
For my 7WSM, 338LM, 338LM Improved I anneal every other firinging. They show very consistent neck tension.
How do you measure neck tension?
Took a new Federal .308 Win. case, loaded it with a Fed 210 primer, 42 grains of IMR4895 and seated a Sierra 165 SPBT bullet in it. Fired it. Deprimed it, cleaned its outside then lightly lubed it. Full length sized it with a gelded die whose neck was 3 thousandths smaller than the loaded round and setting the fired case shoulder back 2 to 3 thousandths. Reloaded that same case with the same components then fired it again and again and again....46 more times before running out of test powder.
Muzzle velocity spread was 33 fps, standard deviation was 10.
Had to trim it back every 10 reloads as it grew up to my 2.10" limit.
Didn't think any annealing was needed.
Friend of mine did a similar test but ran out of powder at 58 rounds. He didn't anneal his case either.
I've used the same type of full length sizing die on 30 caliber magnums getting 14 reloads per case without annealing.
I guess the reason is the case necks didn't change diameters much when sized down; no expander ball was used to work the case neck about twice as much as it would.