RCBS® AR Series Die Sets - RCBS® AR Series dies are perfect for the progressive reloader. These die sets consist of both a Small Base Sizing Die and a new Taper Crimp Seating Die. By including both of these dies in one set, it makes it easier for AR-style and Semi-auto shooters to reload. The Taper Crimp Seater die is more forgiving for the variety of case lengths involved when reloading for these high volume guns. Buckled shoulders and Case Neck crimp bulges basically eliminated when the Taper Crimp is used with bullets that have cannelure.

We asked the RCBS® Product Marketing Manager, Kent Sakamoto, some of the common questions we are getting about the AR Series dies. He was glad to answer. See our Q&A below:

1. So Kent, what makes the AR Series Die Different than lets say a Group A .223 Remington Full Length Die Set?
AR Series dies feature a Small Base Sizing die and TAPER crimp seating die. Previously RCBS only offered Taper Crimp seating die in our Special Order catalog. This is the first time Taper Crimp seating has been offered in a standard die set.

2. What is a Small Base Sizing Die or maybe a better question would be why would I need it?
A Small Base sizing die is a little tighter in the web area than a Full Length Sizer. Semi Auto, pump and lever action rifles tend to have tighter chambers than bolt action rifles, thus requiring the tighter small base sizer.

3. Doesn't a full length die set take care of the same thing?
The difference is only a few thousandths between a Full Length sizer and Small Base, but that can be the difference between chambering and not chambering. Most times a Full Length sizer would have done the job if the sizing die was set properly in the press to cam over. For some reason, handloaders back the sizing die up after contacting the shell holder, when they should be going a ¼ turn further down.

4. Why is a taper crimp essential for AR Style rifles?
For many AR handloaders, volume is the goal and case prep/trimming is not always done. Crimp must be applied to ammunition being used in semi-auto weapons. Taper Crimp is a little more forgiving when various length brass is being used. Less ammunition comes out with buckled shoulders or sprung necks.

5. What about over working brass or lessening the life of my brass?
Small Base sizing will work the brass more in the thick area of the case and possibly reduce case life. Fortunately .223/5.56 brass is plentiful and relatively inexpensive. If the rifle has a good chamber, typically case necks will split before case head separation occurs.

6. What about once fired brass - especially from other AR's?
Once fired brass is typically fine to use. Just because they came out of an AR is irrelevant. Cases should be checked for case head separation as a well worn chamber will ruin brass even on the first firing.