TESTED: RCBS Supreme Die Set

At SHOT Show 2023 we introduced you to the new RCBS Supreme Dies. This time, we have them in hand!


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About RCBS Supreme Dies

In house we have supreme die sets for 223, 6.5 Creedmoor and 6mm Creedmoor.


The Supreme Die Set combines an RCBS Full Length die set with a shell holder and Chamber Case Length Gauge.

The Supreme Die Set is available in eight of our most popular rifle offerings.

    • .308 Winchester
    • 6mm Creedmoor
    • 6.5 Creedmoor
    • .243 Winchester
    • .300 AAC Blackout
    • .223 Rem
    • .300 WIN Mag
    • .30-06 Springfield

What’s in the Box

Each RCBS Supreme Die Set includes a chamber gauge, seating die, full length sizing die and a shellholder. This all in one set gives you all the caliber-specific parts you need to add to your press.

Brass Prep

We set out to load 6mm Creedmoor with the RCBS turret press and RCBS MatchMaster powder dispenser (accurate to 0.04 grains!). We started with resizing and depriming on the turret press. To set the die, I raised the ram, screwed the die in until it was contacting the shellholder, lowered the ram slightly and gave the die another twist for some cam over. Standard procedure followed. I lubed and resized a case, checked it on a headspace comparator and adjusted the die height until we were between 1.5 and 2 thousandths of an inch.

Once resized and deprimed, I primed the cases on the turret press and wiped the lube off each piece before inserting it into the chamber gauge.

You want the case head to sit flush or slightly below flush.

This ensures the brass is properly resized. (With a loaded cartridge in the gauge, you can also check overall length by looking at the position of the bullet in the gauge.)

Checking OAL


As part of a 6mm Creedmoor load development project, we decided to use Staball 6.5 in conjunction with the Area 419 powder funnel. Our chosen projectile was the 6mm 107 grain HPBT from Sierra. We had great luck with them in the past in Federal Premium factory ammunition.

Using a turret press rather than a single stage press makes it easy to quickly move between operations. Swing the seater die into position, place a piece of brass in the shellholder and with the ram up, run the die down until you can feel the die body contact the shell casing. This seating die has a built in crimp feature which is especially helpful for semi-automatics. If you don’t want a crimp, just ensure the die is barely contacting the shell casing. Move the ram back down and insert a factory round to set proper seating depth. With the seater plug screwed out, run the ram up. Tighten the seater plug until you feel it contact the bullet, then lock the locknut. Verify the cartridge OAL and check base to ogive. At this point, the seating die is set up, though small adjustments can still be made.

Seating the bullet is the part of reloading I find most fun. While I only have two dies in the RCBS turret press currently, it can accommodate six, making it possible to have three calibers set up simultaneously. 


Whenever I load ammunition, but especially when I set up new dies, there are a few things I like to check. First I like to check all loaded rounds in the chamber gauge to confirm proper headspace and OAL.

I also check runout to assess the performance of the seating die. These rounds yielded about a thousandth of runout, which is really good. 


The RCBS Supreme Die Set is a great starter and all around kit. In addition to two quality dies, you get the appropriate shell holder and a chamber gauge. While small items, they are incredibly useful. The chamber gauge especially is often underutilized and only purchased by reloaders when an issue arises. 

Get the Gear

Find RCBS Supreme Die Sets and the RCBS Turret Press at RCBS.com!

If you are interested in getting your own RCBS MatchMaster dispenser, check out the product page at Midsouth Shooters Supply!


Winchester StaBALL 6.5 Powder at Midsouth Shooters Supply

Sierra 107 grain Matchking Bullets at Midsouth Shooters Supply

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Gavin Gear

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