October 16th, 2018

PMA Micro-Die Adjuster and Whidden Click-Adjustable FL Dies

click-adjustable die micro-adjusting lock ring PMA Tool Whidden Gunworks

One of the most important aspects of precision reloading is setting the shoulder bump during the full-length (FL) sizing process. You want the amount of “bump” to be precise and identical for every loaded round. However, when you switch brands of brass you may need to change the die position to get the desired bump and case body sizing. And even with the same brand of brass, you may find that you need to adjust your FL die as the number of brass load cycles increases. Brass that has been fired many times will behave differently than new or near-new brass.

Also, even with the same cartridge type, brass loaded for a semi-auto rifle may need more bump than brass fired in a bolt gun. For example, with .223 Rem ammo, you’ll normally want to push the shoulder back farther if the ammo will be shot in a AR15 as opposed to a bolt-action rig.

So how do you make all these needed adjustments for your full-length dies? You can move a conventional locking ring up and down, but that can be a tedious, trial-and-error process. Some guys use shims in one-thousandth intervals, but that still requires taking your dies in and out of the press. Well there is a better way now…

PMA Tool Micro-Die Adjuster

Wouldn’t it be great if you could precisely adjust your FL die up and down in half-thousandth increments, with a simple indexed click. That is now possible with products offered by PMA Tool and Whidden Gunworks. PMA Tool offers a Micro-Die Adjuster that replaces your existing lock ring and can be used with nearly any 7/8-14 full length sizing die. The engraved marks correspond to approximately .001″ of shoulder bump adjustment. Splitting the engraved marks is therefore approximately equal to .0005″ (half a thousandth). Users love this product, saying it adds precision and saves time.

Whidden Click-Adjustable FL Sizing Die System

Whidden Gunworks offers a complete click-adjustable FL sizer die with a special, indexed ring. With Whidden’s patent-pending Click Adjustable Sizer Die system, the die and lock ring work together to allow rapid, precise bump adjustments. One click changes the bump .001″. It’s simple and fast. Included with the Click Adjustable Sizer Die is a shoulder bump gauge. John Whidden (in video below) explains:

“There has become a need for an easier way to adjust the sizer die properly. Until now there have been few options other than trial and error to get the shoulder setback correct. Anyone who has done this can attest that it’s a slow and imprecise job! Our die and lock ring work together to give the user a clicking feel to the adjustment. Each click moves the shoulder bump .001” so you can easily find the exact shoulder bump that you desire.” — John Whidden

General Tips on Setting Up and Using Sizing Dies

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March 23rd, 2017

PMA Micro-Die Adjuster — Try One And You’ll Be Spoiled

PMA Tool Micro Die Adjuster .001 Shoulder Bump full length sizing lift shim

Wouldn’t it be great if you could quickly and easily adjust shoulder bump during the full-length sizing process, without struggling to move die lock-rings by trial and error (or fiddle with shims). Well you can. The PMA Micro Die Adjuster is a brilliant little device that replaces the lock ring on your FL sizing die. It allows you to move the die up and down in precise, tiny increments. The tool has .001″ index marks, but you can easily set your die between the marks to achieve .0005″ (half-thousandth) adjustments.

The affordable PMA Micro Die Adjuster is offered in two versions, an upgraded model with a handy thumb screw for $69.95 (photo above), as well as the original with set screw for $65.95 (photo below).

PMA Tool Micro Die Adjuster .001 Shoulder Bump full length sizing lift shim

To see how the PMA Micro-Die Adjuster works, watch this video by our friend Boyd Allen:

Many of our Forum members now use the PMA Micro Die Adjuster, and they give this specialty tool high praise. Here are actual reviews by Forum members and other verified tool buyers. Read more comments in this AccurateShooter Forum Thread.

PMA Micro Die Adjuster User Reviews

“No more ‘close enough’ for headspace[.] With this tool set-up it’s easy to put headspace exactly where you want it, then repeat it exactly for subsequent batches for the same cartridge.” — JohnF

“I have four of these Micro Adjuster rings and all I can say is that it works and it is repeatable. I bump my brass .0005″-.001″ and this die lock ring will do it without issue.” — TrapperT

“I size brass for four different 6.5×47 rifles (chambered with three different reamers) using a single die, set in the PMA Adjuster. I have to say… I should have bought one sooner. Adjusting it is very quick and repeatable to well under .001.” — /VH

“I’ve been using PMA’s lock ring for some time now and find it to be very easy to adjust to within .0005″ on a single piece of brass. Very quick to do as well. One thing I have found is that if you still need that half-thou adjustment I will run the brass once more at the same setting before I make that .0005″ adjustment and 50 percent of the time that does the trick. The marked increments are in .001″ scale so if you go half way in between there’s your half-thousandth.

PMA Micro-Adjuster vs. Shims

Many hand-loaders have abandoned shims after trying the PMA Micro Die Adjuster:

“Shims [require] you to completely remove the die. That gets old rather quickly after having used the PMA adjustable lock ring.” — Patch 700

“Great product. Shims used to drive me crazy, put a .002 in and get .0035 of change. With this if you want .0015 set it and that’s what you get.” — John B

“I like mine — adjustments are easy and it will adjust very fine. I used to use .001″ shims. Now can adjust my bump as fine as I want.” — Joe139

PMA Micro die adjusterProduct Description from PMA Tool
The PMA Tool Micro Die Adjuster (MDA) replaces your existing lock ring and can be used with nearly any 7/8-14 full length sizing die. We successfully used this tool with sizing dies from Redding, RCBS, Hornady, Lee, Harrells Precision and those made from Newlon Precision die blanks. It allows you to easily make adjustments to your “shoulder bump” as fine as .0005″. The engraved marks on the MDA are equal to approximately .001 inches (true adjustment .000992″) of adjustment to the shoulder bump. Splitting the engraved marks is therefore approximately equal to .0005″. The design of the MDA does not allow it to work with the Forster Co-Ax press. Some custom dies for very short cartridges may require the use of an extended shellholder. Micro Die Adjuster shown in use installed on Custom Newlon/Scott 6mm PPC Die and Harrells Precision Compact Press.

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