Thread: Is "case sizing" a requirement when reloading 12 gauge hulls ?

I believe a semi can lead to bulged shells as the extraction starts when there is still a small amount of pressure in the bore. No problem for a proper brass case but shotgun shells being plastic are marginally stronger than an industrial strength condom and the brass washed steel bases of most take little effort to dent.
Now you interest me, reading your post i take it as your intent to load some bp subsonic loads for the semi, or that's how it reads to me with my readin skills learnt from skool .
Please post or message me when you intend a test run, I would love to see how it goes.