RCBS X-Sizer die

Most of my reloading efforts have been with pistol cartridges. My one set of .223 Rem trials just was not successful, but I’m going to try rifle again.

The one thing I don’t like about doing rifle is all the case prep work. There’s a lot of it, and it doesn’t really lend well to progressive presses. But I found something that, at least from doing Internet research, looks like it’s going to have a lot of potential: the RCBS X-die (RCBS refers to it as the “X die” and the “X-Sizer die”).  From their manual:



The X-Sizer die is a uniquely designed full length resizing die for bottleneck rifle cases. This die not only full length resizes the case, it also limits the growth of the case. This eliminates the need for repeated trimming after an initial trim is done to standardize the case. This die is not intended to shorten the length of the case, rather, as the case grows, the mandrel will reduce the normal rate of growth. This is the result of the case mouth coming in contact with the mandrel stop during resizing. Cases repeatedly sized in the X-Sizer die will grow a few thousandths of an inch initially, and will then stabilize below the maximum case length. Using the X-Sizer die eliminates the need to trim after each shot. X-Sizer dies can be used for full-length resizing with or without the X feature. Partial neck sizing can be done but only without the X feature.



Pretty neat. Google searching turns up good results, with people using it in progressive presses, getting longer case life, and still getting accurate results (perhaps not 100% as accurate as the most finicky of benchrest competition shooters would want, but far better than most of us will ever notice). Of course, there’s a lot of time-savings in subsequent reloads using then X-die, which is where the win is.

So I reckon once I start rifle reloading, I’ll just start with a lot of brass prep, doing initial casework on as many cases as I feel like dealing with on the old single-stage RCBS press (regular full-length resize, clean the primer pockets, debur the flash hole, trim the length according to the X-die instructions, and then mark these cases with a Sharpie so I know “this is a case prepped for the X-die”). It won’t be until the second go-round with these cases that I’ll actually try the X-die, so who knows how long it may be until that happens and then I see how results go. But, I picked up 2 X-Sizer dies, one small base .223 Rem and one small base .308 Win (I’d have gotten a 6.8 SPC if they had a die in that size). I’m curious to see how this will go.


5 thoughts on “RCBS X-Sizer die

  1. If you are shooting out of a bolt gun, you don’t need to full length size a case every time you fire it. I use the Lee collet neck sizer or the Redding bushing neck sizer, and only use the Redding body die every 3-4 loadings (I also use the competition shellholders to repeatably push the shoulders back no more than 0.002″ when using the body die).

    You don’t even have to clean the brass. The top F-class shooters at my club just clean the necks with 0000 steel wool and the primer pockets. I use stainless media and a Thumlers tumbler but you don’t have to if you don’t want to.

    • Good tips!

      For the .308 ammo well…. it depends. If I’m doing plinking loads I’d want to FL-resize and small-base die too, since it could go out of a bolt gun, an M1A or whatever. But if I was doing a hunting load and doing it for a specific gun then yeah, I’d only use brass fire-formed out of that gun and just size the neck.

      Sounds like you use both the Lee and the Redding. Any particular reason for one over the other?

      • The Lee is cheap and easy and gives low runout.

        – Cheap. $20 a die.
        – Case self centers on the flash hole and mandrel, so you have low runout
        – Because it works by pressing the inside case neck against the mandrel, you don’t have to neck turn to get good results
        – For the same reason, you can’t really “oversize” the neck… once it’s pressed against the mandrel you can’t squeeze it tighter, etc.
        – Sizes the entire neck
        – Minimally works the neck
        – No neck sizing lube needed, though I use the Redding dry neck lube (basically graphite) in their ceramic ball applicator

        – Cheap. The fit and finish of the collet is a little rough, so you have to polish the collet and mandrel a little to get them not to “stick” and occasionally eat a case. I also polish the mandrel with 0000 steel wool
        – The size of the mandrel controls how much the neck is sized, and if you want to change that you have to turn it down (for more neck tension) or order a custom size from Lee
        – Sizes the entire neck. Some people think that leaving a bit of the neck unsized helps align the case in the chamber
        – It isn’t available for every cartridge I shoot


        – Well made
        – Available in many calibers
        – Precise sizing control with the various bushings available
        – Doesn’t size whole neck
        – Also gives low runout if done right
        – Minimally works the necks
        – The fancier dies with the micro top allow you to control how much of the neck to size

        – Expensive
        – Works best if you neck turn. The bushings work on the outside of the neck, so if your necks are not consistent, it will push the irregularities to the inside of the neck.
        – Have to buy bushings
        – Doesn’t size the whole neck

        I’m not a volume shooter so even for my AR, I use the collet neck die and a body die (0.004″ shoulder bump), instead of a FL sizer. That sizing button is what really overworks and kills case necks prematurely.

        • This information is awesome! Thank you!

          I’m using RCBS dies mostly because when I bought my reloading equipment off Dock, that’s what he had so that’s what I got. Plus the local Cabela’s stocks RCBS, Hornady, and Lee dies so that tends to be what I use if I need something quick.

          But when I buy dies for 6.8 SPC well… I want to get something good for that. I’ve heard good things about the Redding dies. So the above is very helpful! Thank you!

  2. Pingback: All the prep work… oye « Stuff From Hsoi

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