I've heard and read few articles over small base dies are needed for semi-autos. Are they? What recommendations do y'all have? What's the difference in lamens terms?

I have heard that but in my sig556 haven't had a problem with the LEE regular FL dies I have been using. SB dies resize the portion of the case in the web area that is missed by most FL dies.

If your brass is not swelling much in the web area and can easily chamber a round that was fired in your gun then do not see where SB dies are needed unless you are using brass from another gun that does allow the brass to swell more than your chamber allows for. If I used others brass then I would spend the extra for SB dies for reliability.

Thats what I've read as well as the chambers in most ARs are slightly larger than a Remington 7400 or any other semi related. Whether that is so I don't know.

Chambers are made to +/- dimensions as well as AMMO, SAAMI is the standards organization that governs those dimensions. Ammo manufactures make their ammo to one dimension withing tolerances and Firearm manufactures make their chambers to a specified dimension within their set tolerances. Sometimes you get a tighter chamber than others within those tolerances. The sepcs for each can be found at the link below.


http://www.saami.org/specifications_and_information/publications/download/206.pdf

http://www.saami.org/index.cfm

Makes a lot of sense. Guess that's what I get for not searching just a bit more.lol. Was really looking for the ok to buy dies but I wanted to make sure before doing so. Thanks kmon

I've used Dillon, RCBS, and Lee FL dies on .223.

I load to 5.56 specs. Never had an issue. Sizing is the most important part to be honest with you. I've seen lots of people start reloading .223 and they go to load that first round and it jams in there really good.

Standing on the charging handle doesn't even work to get it unassed.

Make sure your sizing die touches the shell plate then turn it up to a 1/4 to 1/2 turn more closer to the shell plate.

Failure to do this will result in a stuck round in the chamber and I'm not kidding either.

Ask me how I know...

Full length sizing is fine. Full auto I think they recommend small base sizing because of the cycle rate.

You won't need to worry about it.

I did a write up a while ago for reloading 5.56 if you want to go through it.

You can click below...

5.56 reloading

I use RCBS P/N 11101 and I have not had any problems, I use a RCBS Rock Chucker for all my rifle loads