High brass vs. Low brass

[Francis]

I have started reloading shotshell/slugs. I have done reloading in the past (long time ago, galaxy far, far  away) but mostly rifle/pistol reloading. I have all the gear to do 2 3/4" and 3" 12 ga. Shot and rifled slug, to include the roll type crimps using an MEC sizer and low rpm drill press. With all this said, I am having trouble finding the specifictions regarding brass height. I had ordered 100 primed cheddite 3" hulls to do my slugs (hastings reproductions) but got fat fingered and orderd 16 mm instead of 25 mm. Does it matter? In years gone buy, rule of thumb was 3" magnum load =high brass. Field loads =low brass. The manuals I have don't show alot of self defense "00" loads using 3" shells. What they call out are 2 3/4 low brass hulls. Any experiences, links, etc on this subject will be appreciated.

[Graybeard]

Height of brass is immaterial. All that matters is the internal capacity of the case and that varies a bit by brand and type but not by brass height. I think all the Cheddite hulls have same internal capacity but double check that in your loading manual. You DO have the Lyman shotshell loading manual RIGHT?

[Francis]

Yes sir, I do have the manual. I realize that the internal dimensions (holding capabilities) are the determining factor. However, I was always led to believe that the height of the brass on the outside acted as a re-enforcement material. Hence higher brass hulls could generally be loaded to a higher capacity load, such as the sabot slugs or the old magnum self defense loads. I just for the life of me, cannot find any written proof of my beliefs. And I will not load any thing unless I have the right information. I can find lots of 2 3/4" cheddite info, but the 3" seem to be left out. I am sure they are out there somewhere. All of the rifled sabot slugs I have shot, trying to decide upon a brand, have all had a higher brass style shell, which is part of the foundation of my beliefs.
Of course me being wrong is not a far fetched possibility! I'd rather say I don't know and learn, than act like a know it all and get myself or someone hurt.

[Graybeard]

Not true. Shotshells are quite low pressure rounds even lower by far than old black powder handgun and rifle rounds. The small gauges specifically .410 and to a lesser extent the 28 gauge use slightly higher pressures than the larger gauges but all shotshells need to be held down to about 10,500 to 11,000 psi and the 12, 16 and 20 generally are held even lower than that. High brass, low brass or no brass makes no difference.

[rangerwillie]

Lyman shotshell reloading handbook  4Th edition page 27, outside brass height