PMA Tool

PMA Micro Die Adjuster w/ Thumb Screw Upgrade

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For as long as we've been reloading we've always hated setting up our full length sizing dies. We've been using shims to help this along for quite a long while now, but have not really been pleased with them. It seems we always misplace them, or can't find the ones we need, or grab the wrong ones, and they always seem to be covered in rust. For as many years as we've been doing this we've always been looking for a better way. After searching off and on for a solution to this nagging problem we finally have a workable solution. The PMA Micro Die Adjuster.


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” (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 and is not intended for use with turret presses, progressive presses or the RCBS Summit 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.

**Includes Thumb Screw Upgrade for locking the adjustment in place

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43 Reviews

  • 3
    It's a good idea...but.

    Posted by Rand on 30th Sep 2022

    It's works but I took a long time to clean the threads so that it would work. The threads were machined with lots of metal fragments and dirt left. Impossible to adjust until it was cleaned and buffed. Hours lost. But once it was corrected it works fine.

  • 5
    Micro die adjuster

    Posted by ERnie Broe on 27th Aug 2022

    I saw it in use by a friend who is a national champion. I intend to use it for my 6PPC die for precise bullet seating.

  • 5
    Micro die adjuster

    Posted by Larry Boers on 14th Jul 2022

    I have been using one for years for my short range benchrest shooting. I got a zen one one now for my long range shooting kit because it makes changes so easy and it’s very accurate and repeatable.

  • 4
    Micro Die Adjuster

    Posted by Jim Wooddell on 31st Mar 2022

    I am using this with the RCBS Ram Primer Die. I needed a way to adjust and this works way better than fiddling around with a die nut. There is not much pressure needed from the ram so this works great. While resizing brass, I still find it to be a PITA for shoulder bump. I do not think there is a fix for this with current die design.

  • 3
    PMA Micro die adjuster

    Posted by Roger Wilson on 2nd Jan 2022

    Tool is made very nicely but the instructions are not veery clear as to it's usage. I understand the concept but it seems to me the indicator markings are engraved in the wrong direction. If you use the marks ascending, the die moves up in relation to the case. (PMA Note: the ascending numbers are to indicate longer headspace)

  • 5
    Micro die adjuster W/thumb screw

    Posted by Jeremy on 9th Dec 2021

    Absolutely great!!! Set it up as instructions said. Got it dialed in for two thousandth shoulder bump and I have been able to keep my shoulder bumps on all my cases within a half thousandth of each other. Will be purchasing a few more, one fore every caliber I load

  • 5
    micro die adjuster

    Posted by bill blts on 20th Aug 2021

    Great product; easy to make.0005-.001 changes for my" full size" cartridge dies.

  • 5

    Posted by Frank on 29th May 2021


  • 5
    Pma micro die adjuster with thumb screw

    Posted by David Meredith on 8th May 2021

    This tool is fantastic. This tool truly gives you the ability to adjust .001/.0005 at a time, I am hooked. I have one of these for each FLR or shoulder bump die I have.

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