Thursday, June 28, 2012

Review: UniqueTek Micrometer Powder Bar Kit

I've got a pet .40 load that I've been running for about 2 years now: 5.7 gr Alliant Power Pistol with a 165gr Precision Delta jacketed bullet. While it runs considerably over the power factor limit, it isn't quite a major load: ~145pf vs 125 pf with the pill running at ~870fps.

This has been my "go-to" loading: I use it USPSA, PPC, IDPA, etc. It is accurate out of my GLOCKs, the bullets are almost always available (plus they're cheap for jacketed bullets), and Power Pistol meters well and available almost anywhere. You can run this load hot too! Max loads for Power Pistol are somewhere in the neighborhood of 8gr? I run it mild because the gun shoots POA/POI (I've got fixed sights - refuse to have adjustable sights) for me with this... 

Recently, however, I've been trying to develop a loading for Bianchi Cup. Accuracy is a huge determining factor of performance, and a portion of the accuracy is determined by the competitors ability to shoot "The Mover". 

"The Mover" is a Bianchi-target travelling at 10'/second. Shooting it cleanly requires the competitor to lead the target by some amount. The faster the loading is, the less lead required. Additionally, if a load is too slow, the competitor would be required to lead off the paper which makes aiming, which is tough enough, even more difficult. (There is a formula for calculating lead.) 

In order to wring more velocity out of the .40, I've decided to investigate 135 gr loadings. My goal is to investigate a number of different powder combinations and determine a few that will shoot POA/POI at 25 yards, then, after that, start assessing loads on felt recoil and group size. I've settled on Nosler 135gr Hollow Points (match HP's, not defensive HP's) since they're available through Cabela's in Hoffman Estates. A big thanks to Brian Enos for the tip to use 135's.

My biggest barrier in load development up until now has been the Dillon powder bar adjustment. Specifically, the fact that adjustments are not exactly repeatable with it... Now don't get me wrong, once a user has a pet load, you can pretty much set the stock unit and run several thousands of cartridges without worry that the screw will shift - ask me how I know! :) However, for load development, it is simpler to use a better tool for the job: enter the UniqueTek Micrometer Powder Bar adjustment.

I got this over the weekend and had high hopes o just chucking it on the machine and running off rounds! That didn't happen since the unit requires some basic assembly with red locktite, then calibration with ones powders and powder bar. The unit is essentially a micrometer scale with a fine thread that is glued in to the powder bar insert (the part that determines how much powder the bar carries) and then glued into the powder bar itself. The micrometer actuates a fine-threaded bolt to reciprocate, carrying the powder bar insert forward or back. The only issue is to find out how many grains of your powder correspond to the reading off the micrometer. 

I ran several tests with my first two powder choices, Alliant Power Pistol (Flashy? You bet! But that's how I roll) and Bullseye (Dirty? You bet! But GLOCKs don't get dirty!) and developed a scale by measuring several points, then fitting a trendline and equation to them. After that I tested return-to-zero functions, various measurements and found that, truly, the measurements are repeatable - more repeatable than my scale would say!

While this tool isn't for everyone, it sure does make development of a spread of loads much easier.