Here is a nice article from the NRA regarding the Do’s and Don’t s of reloading for Semi-Auto firearms. As you know, Nagel’s has a large selection of Reloading supplies from Manufacturers like Dillon Precision, Hornady, RCBS and more.
From the NRA:
Reloading for Semi-Automatic Rifles: Dos and Don’ts
Going down a point-by-point list comparing and contrasting reloading particulars for a bolt-action and for a semi-auto assumes everyone is already familiar with loading for bolt-guns. It’s best not to assume too much, but since most information “out there” is based on the process-norms for bolt-actions, I likewise have to make some comparisons and contrasts. However, there are major differences between reloads intended for semi-automatic rifles and those for bolt-action rifles. These differences manifest in both tooling and components. Bolt-guns are generally well more tolerant or flexible than gas-guns. I’m thinking of cartridge dimensions and fuel.
Overall: Function first. And safety first. Both goals must coexist.
The brass-alloy cartridge cases are made from is both elastic and plastic. Elastic means it can stretch or expand and then return. Plastic means it can stretch and stay, be shaped and reshaped. Expansion and contraction from firing and sizing hardens brass. The more it gets moved, the harder it becomes. Related also to these properties is that brass flows. The more expansion room available the more it flows. There’s a finite amount of material in a case so the flow creates areas that become thinner or thicker. Since most of this flow is forward, case heads get thinner and case neck walls get thicker.