whats the difference between

hdcolt51

small based rifle dies and regular rifle dies. I have rcbs .308 dies how do I tell the difference? On the die case it just says F L die set .308 win, P/N 15501 group A

Tailgunner1954

Your dies are "regular" full length. The small base dies will have a SB on them (IOW the box would say "Small Base FL die set" on it).

Now for the differences. The SB's size down closer to the rim than a regular die does. They DON'T push the shoulders back any further or reduce the body diameters any more than a regular die does.
If you look at the mouth of your die, you will see a raduis and a small taper leading into the die. The SB has a smaller radius and less of a taper.

hdcolt51

Thank You Sir!

jonk

The purpose being, that SB dies are for cartridges fired in sloppy chambers, or more commonly, semi-auto and MG chambers. Sometimes they need that extra bit of sizing to re-chamber nicely.

CryptoChief

Very commonly used by those rifle competitors using the M1A1 (M14) or rebarreled/chambered M1 Garands. The SB dies help eliminate sticky cases and feed problems, as previously mentioned. Normal FL dies will work fine for loading for bolt guns, as has been my experience.

CC

RCrosby

Have an RCBS SB .308 die that I don't use.
Email me if interested.