Do you want precise control over shoulder bump? In this story we check out Area 419’s ZERO Modular Shell Holder system, and how it can help decrease variability and improve efficiency.
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About the 419 ZERO Modular Shell Holder System
Though this shell holder system is specifically designed for Area 419’s ZERO press, they also offer a version that works with traditional presses.
From the 419 ZERO Modular Shell Holder System Product Page:
As we have done round after round of press testing, both with the ZERO and other presses, we have known that the very best way to get consistent sizing time and again is to have contact between the shellholder and the die. This removes your ability, however, to dial in your shoulder bump – until now. With the new ZERO Modular Shellholder System you can set up your shellholder to your die and have more consistency, more repeatability, and less hassle. It’s a win-win-win.
Available in either a Zero specific mounting system or a traditional shellholder this allows you to dial in should bump with a set of 6 precision ground stainless steel inserts .002″ at a time.
The Kit comes with:
– A Base (meant for ZERO or Traditional presses, your choice)
– THREE Shellholder/Extractor tops, sized for 223, 308, Standard Magnum (or similar)
– SIX Precision Ground headspace inserts ranging from +.002″ to -.008″
– Aluminum Storage Block
How to use the shim system
Six shims/headspace inserts come with the set, ranging in thickness from +.002″ to -.008″. This provides ten thousandths variance we can fine tune to refine contact between the top of the shell holder and the bottom of the die. The goal is to eliminate air gaps in this space, which undermines consistency. Additional factors, including varied brass hardness, can compound this matter. At the end of the day, you want to resize batches of brass as close to the exact same specifications as possible.
The ZERO modular shell holder system includes shims and three caps. Each of these caps is sized for a different case rim type: .223, .308, and standard magnum (or similar). Take the shellholder base, insert the desired shim and thread on the cap for the appropriate caliber. Rather than have a unique set of shellholders for each caliber, Area 419 has simplified this process by offering one set of shims with an assortment of caliber-specific caps.
The complete unit (base, shim, cap) slides onto the ram of the press. Note that you can select (on the Area 419 product page) either standard press shellholder type, or the Area 419 Zero type (uses threaded cap to secure to ram).
Sizing Experiment
First, we pulled four pieces of brass with the same headspace. The goal was to use different shims and evaluate the difference in base to datum measurements.
Using a Bullet Central Micron Sizer Die and the 0 shim, the measurement was -0.0035″ (relative to unsized brass). This means the shoulder was bumped 0.0035″.
Using a Bullet Central Micron Sizer Die and the +.006″ shim, the measurement was -0.0005″ (0.0005″ shoulder bump).
Due to brass springback, we expected, and found a difference between the shim thickness change (delta) and the actual shoulder bump observed. We had a difference of approximately .003″ rather than the 0.006″ difference in shim thickness. This is due to spring back on the brass.
Get the Gear
If you’re looking for a great way to get more precise control over your shoulder bump, Area 419’s ZERO Modular Shell Holder System is the way to go!
You can find all of the above gear at the links below! Prices current as of 3/7/2022.
Area 419 Shell Holder System (for Zero press and for conventional presses, select on product page)
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Thanks,
Travis Fox
