Quoted:
The maximum length & the trim to length are available should you search that. Here they are. 1.750 & 1.760. Sounds like you trimmed the cases with out knowing how much to remove. The primer crimps were removed either by swaging or by a taper reamer. Neither process harms the primer pocket's fit to the primer.
Neither process shortens useful case life. Other mechanical influenced do. How is it you say you assume "they don't trim", & that "your trimmer took a lot of brass off."???
Do some reading on rifle case preparation in a reasonable current reloading manual to become acquainted with the entire process.
I think you either badly misread my question or I failed to write it in a coherent style. I'll respond for clarities sake.
Rest assured that I know the trim to length and max length. I trim to 1.750. Most once fired LC brass that I encounter is between 1.750 and the max length of 1.760. The black hills LC brass I trimmed last week was all very close to 1.760 and some a little over. I was brief on that point because I wondered if it was known how they process their brass. Do they trim it or just weed out overly long cases? It seamed a little on the long side. (some beyond 1.760 after measuring some I haven't processed yet)
However, that was more of an observation. My main question was how they remove the crimp. The primer pocket is looser on the black hills LC brass on the first reloading than on LC brass I have loaded several more times. I have processed a lot of crimped brass by using a reamer. The black hills looks like it was processed using a very aggressive reamer, and I'm wondering if that is why the pocket is looser. In terms of primer pocket life, it appears to be more like FC crimped brass in that its looser than other brass.
Perhaps I should have been more clear in asking if anyone else has noticed this, or if the 50 I processed were just an odd batch. Either way, thank you very much for your concern and recommendation that I read more on case prep.