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Feb
19

The UniqueTek Micrometer Powder Bar upgrade

I love my Dillon press. Absolutely the best press I’ve used (and I’ve used several non-Dillon presses, too – not owned, but operated…). As good as they are, they can always be made better (in my opinion… probably not in Mike Dillon’s, if I had to guess!).

One of my biggest pet peeves with the Dillon powder measure is the stock adjustment screw. It’s just a bolt that’s run straight into the piece that adjusts the size of the powder cavity. There’s no way to gauge how much you’re adjusting it (other than ’1/8 turn-ish’), and the threads on the bolt are quite coarse, so your adjustments are anything but precise. This can lead to frustration when you’re trying to dial a load up or down a tenth of a grain or two.

The solution?

The UniqueTek Micrometer Powder Bar upgrade kit! I’ve been using one for a couple of years, now, and I have to say I consider this to be mandatory equipment. No more guessing how big an adjustment I’m making, no more fiddling and fiddling until I finally get the right value dialed in. This thing is the bomb!

The micrometer solves both problems with the OEM solution. It has very fine threads, so you can easily and confidently make very small adjustments (in fact, I can reliably adjust down to .025 grains – probably finer), and the micrometer markings allows you to see precisely how much you’re moving the screw.

I ordered the kit and installed it myself. The process was fairly simple, but does require a little bit of patience. Basically, you remove the old screw (and throw it far, far, away!), clean everything up, then check the alignment of the micrometer in your measure, and insure that you have it oriented so that you can see it while it’s on the press. Then, you use the included Loctite (some really strong green stuff – not the usual red or blue) to secure it in place. Now comes the patience – you have to wait a day for the Loctite to set up, so don’t go installing this thing a couple of hours before you have to load ammo for a big match! If you’re not so inclined, UniqueTek will install one on your powder bar for you.

The micrometer also makes another feature possible. You can actually calibrate the micrometer to a given lot of powder, and use that to reliably predict how a change in your powder bar setting will equate to a change in charge weight. UniqueTek actually has a spreadsheet they’ll send to you that will help in predicting the right setting for a given charge weight. CAUTION! You should always weigh the charge to double check that you’re dropping what your predicted setting is actually throwing! That should probably be obvious to everyone, but it doesn’t hurt to repeat it.

In practice, I find UniqueTek’s suggested method and spreadsheet a little too cumbersome for my taste. It involves weighing a lot of charges, and that takes a lot of time. In the end, after I set my initial charge with a new powder, what I find much more useful is to know roughly how big a movement on the micrometer will result in a tenth of a grain change in powder charge. All of the powders I’ve tried so far have been very linear. So, I weigh charges at a couple of settings (usually 1.00, 2.00 and 3.00, on my setup), and find the difference between them, and then divide by 100. That gives me “tenths of a grain per hundredth of inch” – for example, with my current lot of N105, I get 4.9 grains at 1.00, 7.6 at 2.00, and 10.4 at 3.00. That’s 5.5 grains over 200 “hundredths”, or .0275 grains per hundredth. That gives me roughly one tenth of a grain per 4 hundredths movement on the micrometer. It’s surprisingly accurate and predictable. What’s more, I can write down a setting, and return to it later, and the charge will weigh the same. This allows me to quickly find new charge settings, as well as return to older ones without having to fidgit for a long time with the OEM adjustment screw.

I do follow one process to avoid the effects of backlash – I always approach my setting from a lower number. So, if I’m at, say, 3.00, and I need to move to 2.75, I dial the micrometer down past 2.75 (say, to 2.65), and then back up to 2.75. I then throw a couple of charges and return them to the hopper to make sure that everything is set before I weigh the charge. I don’t see any notes about backlash on UniqueTek’s website, and I don’t know if they would feel this process is required, but I follow it just to be consistent.

One final note of caution – you can’t share settings with someone else. Every powder measure and powder bar are different, and every micrometer is installed differently, so the settings on my bar are not going to yield the same volume as yours. We might have the same change rate in our adjustments, but our starting points will be different, so our absolute numbers are going to be off from one another. So, be careful with what data you use from someone else.

I like the Micrometer so much, when I sold my 550, I moved the powder bar from my new 650′s powder measure, and kept my old powder bar. It might also be interesting to note that my settings don’t appear to have changed vs. the old powder measure. I’ll put one of these on every powder measure bar I have in the future, for sure!

About the author

DaveRe

USPSA Grand Master, NRA Instructor, http://re-gun.com/about/

Permanent link to this article: http://re-gun.com/2011/02/the-uniquetek-micrometer-powder-bar-upgrade/

1 ping

  1. Make your scale more accurate | Re-Gun says:

    [...] quick note about the video. You might notice that I’m using a UniqueTek Powder Bar Micrometer, but my first adjustment didn’t nail the charge weight down? My notes were taken off of a [...]

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