On Target Product Review: RCBS AR Series Die Set (for 308)

The RCBS AR Die series is designed for reloading semi-auto rifles. They come in the distinctive black box and work very great with progressive reloaders such as the Dillon 550B.
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Editor’s Note:  This is the twelfth article in our ongoing Christmas buyer’s guide. While the items we’re highlighting are not generally stocking stuffers, this one sure is. Stay tuned for more great gift ideas targeted at your favorite gunslinger.

The lure of the semi-auto rifle has swept this country. Head out to the City and County of Honolulu’s Kokohead Range at on a weekend and you’re likely to see 60% or more of the benches with AR 15s or some other MSR pointed downrange. (Of course we’ll have to wait till the range reopens while repairs are made on the berm).


The old range would allow you to shoot out to 440 yards. Not terribly distant by mainland standards but the swirling winds on the ancient volcano’s ridge don’t make it easy to hit those plates on the best of days. A 5.56 bullet that weighs in the 50-60 gr range is blown around like a piece of tissue. A heavier bullet, in the neighborhood of 75 gr, has a much better chance of hitting that elusive plate—but even then it’s not a sure bet.

On those gusty days I pined for a .308. Now there’s a projectile that would do the trick. It’s also the next logical platform for an “MSR” junkie who wants that long range accuracy that an AR 15 can’t provide. This is also a chambering that the serious shooter is going to be loading. With the price of 308 rounds going for approximately $1 a cartridge here in Honolulu, there’s really no alternative to reloading.

The smaller based sizing die brings the cartridge closer to its original specs.

Now that we’ve decided to load for this round, the next step is to choose the right implements. The heart of any reloading endeavor will be to pick the right die set. Are they a commodity?  Well it’s not a cut and dried answer, as you’ll soon see. Reloading dies don’t have the complexity of triggers for thermonuclear devices, but must be very precisely machined. Some are tuned for special tasks.

For this review, we looked at RCBS, which is reputedly the largest provider of reloading dies in the U.S. Founded in 1943 by Fred T. Huntington, the company’s first digs were in the back room of his dad’s Oroville, California laundry and dry-cleaning plant. RCBS, an acronym for “Rock Chuck Bullet Swagers”, is most definitely no longer a mom and pop enterprise.

They are owned by the publicly traded defense giant ATK, which also owns Bushnell, Alliant Powders, Federal Cartridge, Speer, Blackhawk and CCI.  Yes, they are big. The gun industry is highly balkanized and I suspect in the next decade or so more larger concerns like ATK and hedge funds and will continue to acquire quality companies where they see a growth potential.

It’s life in the 21st century.

 The mom and pop firms are often stymied by lack of capital and nowadays are under pressure to either grow or be crushed. The public companies have the resources, liquidity, distribution and the wherewithal to hire the management, marketing and PR people that will take the company to the next level. At least that’s the theory.

I know zilch about ATK’s corporate culture but every interaction I’ve had with the companies they own has been positive. If customer service is any indication, management seems to have had the sense to allow RCBS the autonomy to run their own show. That’s a good thing because I can’t think of any demographic pickier about CS than gun owners. The “gun industry” is one of the last bastions of enlightened customer service.

After working in Silicon Valley for many years, I can assure you that often the first thing to go during a merger is customer service. That’s because guys with green eye shades, who always think they know better, love to whack the “excess” from the payroll. I haven’t witnessed that with RCBS or the other ATK subsidiaries I’ve dealt with.

Well enough of my erudition.

Semi autos are fussier than a bolt action rifle in regards to the dimensions of the cartridges they can digest. Reducing the size from the base to the shoulder will ensure that the cartridge chambers and extracts reliably.

So why choose the RCBS AR die set?

First off they are designed to work with a progressive reloader. If you’re like me, and began loading for handguns using the Dillon 550B, the RCBS is perfect. After all, if you’re shooting a semi, you’re going to be loading for volume. That doesn’t mean you’re not interested in precision but, chances are you’re not going to be as anal retentive as someone loading for bench rest.

Thus the RCBS AR series dies (which come in a distinctive, black box) differ from the standard dies. If you’re going to load for an AR, a semi-auto or a lever action (as opposed to a bolt action) you need to understand how the specs for the AR series differ.

The AR was originally designed for military use, hence they need a roomier fit between cartridge and chamber in order to favor reliability of function.

However, the requirements for accuracy are addressed by the cartridge as being as close as possible to the dimensions of the chamber. Thus we have two opposing requirements; loose fit for reliability and tight fit for accuracy.

To address this in the AR, RCBS has created a set of dies that allows close control over the tolerances of the cartridge. This allows the reloader to tailor the cartridge to get the best possible balance between auto feeding reliability and accuracy.

Smaller based sizing dies, the kind that RCBS manufactures for the AR series, bring the cartridge much closer to its original specs. It does this by sizing the cartridge from the shoulder to the base a few thousands of an inch smaller than a full-length sizer die is able to do. Reducing the size will ensure that the cartridge chambers and extracts reliably.

So theoretically shouldn’t a full size die also do the trick?

Yes and no.

According to RCBS Product Marketing Manager, Kent Sakamoto, a Small Base sizing die is a little tighter in the web area than a Full Length Sizer. This few thousandths of an inch difference between a Full Length and Small Base sizer is critical. That said, a Full Length sizer die would have accomplished its job of correctly sizing the brass if the die was set properly in the press. Ken says many hand loaders back the sizing die up after contacting the shell holder, when they in fact should crank the die down another ¼ turn. That’s right, crank it down. Just that action can make the difference between a round chambering–or not.

The RCBS AR set also includes a taper crimp seating die. Ken says this is the first time the Taper Crimp seating has been offered in a standard die set.

A Taper Crimp is more forgiving when you have brass that’s not uniformly trimmed. Tapering is also a necessity when you’re shooting semi-auto. A tapered crimp helps ensures the bullet stays put in the case.

Why is this important?

Let’s face it, for AR handloaders (unlike benchrest shooters and other bolt action aficionados) want to crank out a large volume of ammo. In their zeal to do this, case preparation, which includes trimming may not always get done.

A Taper Crimp is not only more forgiving which you’ve got brass that not uniformly trimmed but necessary when you’re shooting semi-auto. The upshot: less ammo comes out with buckled shoulders or sprung necks. RCBS recommends that rifle bullets with cannelure be used with a taper crimp.

Setup of the dies on the Dillon 550B went smoothly. The only thing I needed was an extra toolhead. Once acquired, we followed the instructions. The RCBS dies are no different to set up than others. Just make sure the cases are lubed properly to avoid the dreaded stuck case syndrome. 

The last item to note is that the set is not expensive. Price for the two-die set is under $60 on Amazon. If you’ve got your heart set on a 308 from LMT, PWS or a similar marque this is the die set you need.

Photos courtesy of On Target staff.

Questions?  Comments?  Contact us at ontargethawaii@gmail.com

Rob Kay writes about firearms for Hawaii Reporter and is the author of How to Buy an AK-47.