300BLK - Small base dies?

[LanceS4803]

Going to start reloading for 300BLK for use in an AR platform and saw that Midsouth offers two options in RCBS; full length and small base (with the small base dies being $20 cheaper).
I have never used small base dies, but understand the concept.
Are small base dies needed, or desirable, for 300BLK? (And dang, dies have gotten expensive!)

 

[TiminTN]

Small base all the way on AR platform. Thats their intended purpose.

 

[Omega]

I don't think so, I first used Lee dies to convert 5.56 to 300blk, at first had a slight issue with the case not fitting the Sheridan case. Fixed it at first by taking a little off the case holder, but then switched to RCBS case holders and didn't have any other issues. I also got some Hornady dies and they also have no issues resizing the cases even with a unaltered Lee case holder. Small base dies do work, but, IMO, they work the case too much for just everyday loading, maybe as a second set, but not for your one and only set.

 

[Lone Hunter]

Also it will depend on the size of your chamber and if your brass is new or fired in chambers larger than yours and the regular dies can't size the brass down enough especially at the .200 line or web area. I have both sets of dies and don't think I have used the SB die set much But in case I need them I have them.

 

[MUP]

Also it will depend on the size of your chamber and if your brass is new or fired in chambers larger than yours and the regular dies can't size the brass down enough especially at the .200 line or web area. I have both sets of dies and don't think I have used the SB die set much But in case I need them I have them.

I've got a standard Lee die set for loading my AR with and it sizes adequately for my chamber also. SB dies do take the guesswork out or the chance that the standard die set won't size the case to fit a particular AR barrel.

 

[Billboy]

I've never found the need for a small base die for any of my stuff, but I can see a situation where you might need it if your chamber is "tight". Although expensive, I'd go with a standard die first. The small base die will work your brass more and lead to shorter brass life if your chamber is "normal".

 

[DaveB]

I have both for my .308 and .223 rifles.

I use a lot of once-fired brass and find bolt close & lift issues if I do not use the SB dies at least the first time through my chambers. If you are loading crimped primer brass might want to give the SB gear a try.