Understanding Shell Holders in Practice
Shell holders are the small circular discs that sit at the bottom of your reloading press. They grip the base of the cartridge case and push it up into the die. RCBS makes them in several sizes, and getting the right one matters because using the wrong shell holder will either prevent the die from threading down properly or cause the shell holder to bind before the case is fully sized. The chart exists so you can match a shell holder number to the cartridge you're reloading. It is not complicated, but it is easy to mess up if you are rushing. Here is how to actually use it.
Rcbs Shell Holder Chart
Below is the standard reference. Shell holder numbers run from 1 through 7 for most common cartridges, plus a couple of specialty numbers. Each corresponds to a cartridge family based on base diameter and rim configuration. Shell Holder 1: .221 Remington Fireball, .222 Remington, .223 Remington, .4. Remington Magnum, .30 Carbine Shell Holder 2: .25-08 Remington, .270 Winchester, .30-30 Winchester, .308 Winchester, .30-06 Springfield, .35 Remington
Shell Holder 3: .243 Winchester, 6mm Remington, 6.5-08 A-Square, 6.5 Creedmoor, .280 Remington, .338 Federal Shell Holder 4: .300 Blackout, .300 Whisper, .350 Legend, .450 Bushmaster Shell Holder 5: .22-250 Remington, .22-250 AC, .257 Roberts, .260 Remington, 7mm-08 Remington, 7mm Remington Magnum, .300 Remington Ultra Magnum
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Shell Holder 6: .300 Winchester Magnum, .338 Winchester Magnum, .375 Remington Ultra Magnum, .458 Winchester Magnum Shell Holder 7: .45-70 Government, .45-120 Winchester, .50 Beowulf Shell Holder 8: .50 Action Express, .50 AE
Shell Holder 9: .22 Hornet, .219 Zipper Shell Holder 10: .454 Casull, .45 Colt, .480 Ruger Shell Holder 11: .41 Magnum, .41 Remington Int'l
There is also a Shell Holder 0, which is less common and used for a few specialty cases.
How to Actually Size Your Cartridge Using the Chart
The process is straightforward once you understand what the numbers mean. Install the correct shell holder into the ram of your press. Slide your case into it. Then lower the die until it makes firm contact with the shell holder before the case is even inserted. For full-length sizing, you typically back the die off a quarter turn after contact to prevent bottoming out the press ram. For neck sizing only, you thread the die in further until it barely touches the shell holder. I learned this the hard way on a batch of 223 Remington brass I was prepping for a PRCA match load. I grabbed shell holder 1 because that is what my previous press used, but I had just switched to a different die with slightly taller threads. The die would not screw down far enough to size the cases properly. The shell holder was correct, but the die clearance was wrong. I ended up threading an adapter ring between the die and the shell holder to compensate. It worked, but it added maybe ten minutes to my session and should have been obvious from the start.
Pitfalls That Nobody Warns You About
Most beginners think the chart is the end of the process. It is not. The shell holder number tells you the cartridge platform, but it does not account for variations in your specific die or press. Different die manufacturers have different thread heights. RCBS dies are generally consistent, but after-market dies may require you to adjust how far the die screws into the press even with the correct shell holder installed. Another issue is worn shell holders. After a few thousand cycles, the internal knurling that grips the case can smooth out. A case that should stay firmly seated will slip during the sizing stroke. When this happens, you get inconsistent headspace and sometimes the case base gets scored. Inspect your shell holder periodically. If the case drops out when you tilt the holder, replace it. They are inexpensive enough that holding onto a worn one does not save money. I also ran into a situation with 6.5 Creedmoor brass where the RCBS chart lists it under shell holder 3, but my press setup kept producing case Headspace dimensions that varied by about two thousandths of an inch from batch to batch. The problem turned out to be that I was using a Lee factory crimp die on top of the RCBS full-length sizing die. The combined force was pushing the shell holder slightly into a different position each cycle. I switched to a separate die station and the variation dropped to under five hundredths. This is the kind of thing you only notice when you are already measuring precision and wondering why your groups are inconsistent.
What the Chart Does Not Cover
The RCBS shell holder chart is limited to standard full-length and neck-sizing operations. It does not address progressive press setups where multiple operations happen in sequence, and it does not cover dies that require specialized shell holders for specialty operations like bell molding or flare dies. Some specialty dies from other manufacturers may also need shell holders that differ from the RCBS standard for the same cartridge. For example, Hornady makes shell holders with slightly different internal diameters than RCBS, even for the same cartridge number. If you switch between brands of dies without checking the shell holder compatibility, you can get sizing issues or difficulty loading cases back into the chamber afterward. Another limitation is that the chart does not account for wildcat cartridges. If you are building ammunition for something like a 6.5 Grendel or a 6mm BR Norma, the standard RCBS chart will not list it. You have to determine the correct shell holder empirically by matching the base diameter and rim profile to the closest standard listing.
A Note on Alternatives
If you find the RCBS system restrictive for your needs, there are other options. Wilson Combat offers shell holders that are machined to tighter tolerances and tend to hold cases more securely over time. For precision benchrest work, some reloaders use Wilson shell holders exclusively because the consistency is noticeably better across thousands of cycles. They cost more upfront, but the durability difference is real. If you are reloading competitively or in large volumes, the investment is worth it. For casual reloaders shooting at the range occasionally, the RCBS system is perfectly adequate. The chart works as intended, and the shell holders are cheap enough to replace when they wear out. The main thing to watch for is ensuring your die and press are compatible with the shell holder you select, and that you are not mixing components from different manufacturers without verifying fit.
Quick Reference for Common Cartridges
.223 Remington / 5.56 NATO: Shell Holder 1 .308 Winchester / 7.62 NATO: Shell Holder 2 .30-06 Springfield: Shell Holder 2
6.5 Creedmoor: Shell Holder 3 .270 Winchester: Shell Holder 2 .243 Winchester: Shell Holder 3
.300 Win Mag: Shell Holder 6 .45 ACP: Shell Holder 9 When in doubt, measure the case head diameter with calipers and compare it against the shell holder specifications. That is more reliable than guessing based on the chart alone, especially for older brass or non-standard cartridges.
