Okay, I was wanting to buy some Military brass for reloading and it was stated that small base dies were needed to full length size. New to me.

What are they and why are they needed? Are they used if reloading for military type (AR/Colt/etc.) or so that the brass can then be used in commercial firearms (Rem,Savage,etc.)?

Thanks for educating me!

I bought 2000 pieces of that 308 a few years ago. Why you need the small base dies is because it Was used in a m60 machine gun with a big chamber. It is best to resize them first with a regular die Then use the small base. I hope you have a real good press bolted to a good table and a stuck case remover.Remeber to trim them too.
Steve

When I was forming 7mm TCU out of commercial .223 brass I ran into the base size problem -- the bases were simply too large to chamber in the tight 7mm TCU chamber (a Contender barrel). Looking around my reloading bench I discovered that I could run the lightly lubed .223 brass completely through an old Lyman .38/.357 full length sizing die (all steel, no carbide, decapping assembly removed) using a pusher made out of a short length of brass rod crimped into a cartridge case (in this instance I used a .32 ACP case and shell holder). This worked just fine and spared me the expense of a small base die. There's probably a die out there that can handle .308 size heads (maybe a .45 acp non-carbide die?). I'm interested in your findings if you opt for something made on the bench rather than store-bought.

I have yet to need a small base die despite using thousands of military cases. I did once assist a friend who was told he needed such a die for ammo to use in a BAR. That was not the problem. He simply needed to trim another .002" from case length! His ammo works perfectly now. .308 using 7.62 NATO cases, yes fired in M60 MGs.

Try the standard dies first. If you have problems fully evaluate and deal with those problems. You may not need SB dies.

sir
A few years ago my wife and myself were very blessed when we were made a gift of six Belgian Browningg that belonged to a couple that hunted together all there lives.Two to the weapons attached themselves to us. They were a 300Win. Mag and her 30-06 , both BAR'S
On attemting to work up a load I descovered chambering problems with both rifles.Now I was really pissed. I phoned my learned loading colleges at R.C.B.S. and was told that I needed to use a small base resizing die. The reason they gave me was because the small base die re-sets the case back to factory specs.