I've shot BP for 55 years and only started reloading the new fangled cartridges about ten years ago - my question is in regards to rifle dies. I'll add that I reload 30-30 and 8 X 57 but will be adding .308 and 30-06 - have the brass, dies, molds, etc. and am looking for rifles over the winter. I'm thinking a single shot 308 and a bolt 30-06.
Now to my question. I have run across "small base" die sets both in posts and have seen them listed in the S & S - IIRC - in reference to 308 and 30-06 but I'm sure they are probably made in other calibers?
My reloading - for 308 and 30-06, I picked up Lee sets that while used are really "new". I de-prime all of my brass with a universal de-priming die - FL size in the Lee FL die with the depriving/expander stem removed, expand with a Lyman M die, use a seating die and usually the Lee collet crimp die or similar.
In 308 - I've made some dummy rounds up just to try the dies and see the results. For the 308, I did buy a Hornady "cartridge gauge". My brass stash is mixed head stamp commercial brass - 1X fired and range brass. In the Lee FL die, it seems to work jus fine and the cases slide right in to the cartridge gauge like they should - so I'm guessing everything will be kosher when I actually load some up for real.
In reading, I seem to remember the "small base dies" being correlated to semi-autos of the most part.
Can someone explain the difference between (we'll use .308 dies as an example) a regular normal FL sizing die and a "small base die"? What does the small base die do to the cartridge casing as opposed to a regular die. I'm assuming that it makes the base smaller in some manner? That seems like a hard thing to do given the brass in the base of a cartridge casing at the base. Why is it necessary to use a "small base die" in relation to a rifle or rifle type? Maybe I'm misunderstanding but I'm assuming the it is the FL die that is being talked about since that is the only one that would really have anything to do to the base - but if it makes the base a tad bit smaller, what about the portion in the shell holder?
Thanks for the lesson - greatly appreciated. Been wondering the "whats" and "whys" of small base dies for awhile but didn't want to appear to be ignorant. So far I haven't run across an explanation when searching - mainly references to their use for certain rifles but no explanation why they are required.