Random Thoughts on the Star Powder Tube Magazine

[ARTINCT]

As a long time modern Benchrest rifle shooter I am quite familiar with much of the current equipment associated with that exacting sport as it relates to reloading and powder charge throwing.

If one examines the typical Star powder tube magazine, be it plastic or metal, one thing that is present in most all benchrest powder measures is missing from the Star.  The part that is missing is the single perferation isolation baffle.

The typical benchrest "click" type of micrometer powder measure has an internal reservoir chamber that is separated from the "bottle" or powder magazine by a metalic baffle that has a single hole about the size of a pencil or felt tip pen body.

The purpose of this baffle is to mantain a specific and consistant volume and pressure of powder above and around the dispensing orafice.  The perforated baffle isolates the larger quantity of powder (and always diminishing) from the measuring chamber. Thus as one reloads round after round the hole in the baffle allows a replenishment of powder that is being drawn from the reservoir chamber by the slide bar.   It keeps the weight and compression equal at all times on the mechanical dispenser regardless if the magazine is very full (heavy) or nearly empty (light).  As long as the internal reservoir is full, then in theory, all dispensing mechanics being equal, one has a greater chance of equal powder throws or measures.

I notice that this concept of the powder isolation baffle is pretty much missing from the typical Star powder magazine.    I have fashioned one out of aluminum and have inserted it into my Star plastic powder tube about 2 inches above the metal funnel which screws into the OO powder slide top.

The long distance black powder rifle cartridge shoots all use baffles in their ancient B&M loaders.  Baffles are present in all the Harrel's benchrest and scheuzen precision measures.  Also the coveted Jones and Culver benchrest measures employ baffles as well.

Has anyone else experimented with a single perferated baffle?

Also,  the three or four indents on the Star's vertical powder cam actually serve a major purpose as far as I can see.  If you take the powder magazine off of the magazine holder and can see the operation of the powder bar in action, the little indents on the cam actually "SHAKE" the powder slide both forward and back to achieve a "vibrational settling" of the powder.   The speed in which you operate you Star should probably be such that the vibrational settling is the same time after time if you are after consistant powder charges.

Benchrest shooters achieve vibrational settling by tapping the lever of their powder measure two to six or more times for each powder charge upstroke.  Of course there are those who only do the tap once...
But non the less, the guys at Star were onto something with those fine indents on the cam.

If you cam is so old and worn as to have the indents heavily rounded down or pretty much gone, then I would suspect your powder charge thows are not as consistant as they could be.

I welcome thoughts and comments on this.

I also welcome some of the more talented and gifted craftsment here to fashion a Star tube with at least one internal perforated baffle as part perhaps of a two part plastic and one part turned aluminum baffle into which the plastic magazine fits.

Cheers...

[tony barone]

The powder magazine that came with my Star has an aluminum flat baffle with a 3/8 diameter hole in it. Is that what you are referring to?.

[tabranch]

All three of my Star powder measure reservoirs have the internal baffle also.

[rbwillnj]

Actually, I've been amazed at how consistant powder drop weights are with a Star.  I think the internal baffle and the vibrations caused by the notches in the powder slide cam are the main reason.   I have a Sartorius laboratory scale that measures +/- .01 grain.  When ever I check charge weights they seem to be with in +/- .05 grains.

But I guess there is always room for improvement.   Maybe this design from one of our other members is what your looking for http://www.ray-vin.com/tech/hack/baffle.pdf

[starman]

I have to agree with rbwillnj on this one but I do think powder like bullsey will metor very well and last of all I do looks at my target I put 5 shots in the same hole that is good enough  for me and then just go to another gun well just my thought

[Star73]

This subject has me baffled. Both my machines are std powder resevoirs with baffles. I thought they all were so constructed. I recall some yrs ago an article on loading for competition accurate loads which touted the stars because they offer an increase in quality because of powder measuring consistency.
Ron

[ARTINCT]

Well this feedback is quite informative.  I have three Star machines at the moment and none of them had a powder baffle in the powder magazine other than my first Star (which I retrofitted with a baffle).   

I am not the original or first owner on any of my machines so I cannot say, if along the way, my powder magazines have had baffles removed or lost when the magazines were restored.

So did Star provide a perforated powder baffle as standard equipment in the powder magazine?

[rbwillnj]

The Star powder magazine has a powder baffle, it's maybe just not up to the standards that you are familiar with from your Bench Rest rifle experience.   The aluminum disk on top of the brass base acts as a baffle.  Most of the weight from the column of powder is distributed over the aluminum disk, so it tends to keep the charge weights pretty consistent as the volume in the powder magazine decreases.   However, a baffle like the one in the PDF that distributes the weight of the powder column off to the side, and not directly over the powder exit hole would be an improvement over the Star system, and no, Star did not provide such a baffle.

Quite a number of us on this forum are Bullseye pistol shooters, a sport that requires a fair degree of accuracy from a handgun.   Personally I've been very satisfied with the consistency in drop weights because of the results I get both in group size and in chronograph results.   Now if I were a silhouette shooter I might be looking for even better results.

I thought the Bench Rest guys weighed out individual charges.

[ARTINCT]

Hi Bruce:

So then it appears that the powder baffle, if present in a Star Powder tube, is or was a retrofit item provided by the owner and or could have been provided by Star?

Regarding benchrest powder throws... most reloading (decapping, shoulder bumping and slight neck sizing, powder charging and bullet seating) is done at the range, outdoors, usually under a covered shed on picnic type tables or similar type tables in a designated reloading area.  

Due to wind and weather, this does not allow for weight measurments of any accurate manner.  The typical benchrest shooter uses a micrometer type powder measure, such as a modern Harrell measure or an older Culver or Jones measure (among others).  These measures have an audible "Click" type ball detent micrometer for setting charges.   Usually for a specific bullet and gun and set of cases, a consistant powder throw is achieved at the range without any weight measurment but rather a volumetric measurement.  

At home in a controlled environment, you can weigh the click load to define the weight but when discussing powder charges, powder type, lot number and click number information is exchanged.  On certain days when the weather is hotter or cooler, the clicks may be added on to or reduced by +/- one or two clicks.

In any case I find the Star powder dispenser to be quite accurate for my purposes with or without a baffle as long as you keep the powder column in the powder magazine as close to the same level within reason.  I suspect that throws with only 1/2 inch of powder in the magazine would differ in weight vs throws with a full magazine of powder.  That would stand to reason.

Thanks for the inputs on this guys...

[Star73]

As mentioned by Bruce & myself the baffles he (Bruce) describes are original...factory....Star.

[ARTINCT]

Thanks Ron, that is good to know.  Somehow my machines lost theirs along the way to me.
Art

[rbwillnj]

Art,  I think there is some confusion about just what each of us is calling a baffle.   The Universal machine that I sold to you has its original factory baffle, the aluminum disk above the brass base.  Star did not offer any other baffle to my knowledge.

Bruce

[rbwillnj]

OK Art ,  you got me curious, so I did a little, maybe unscientific test. 

I have been loading 38 Special Wadcutters using ~2.6 grains of 700X.   I let the powder level in my 12" powder magazine get down to where it was only 1/2" above the aluminum baffle (way lower than I would normally allow).  I dropped 10 charges and weighed them.

2.62, 2.60, 2.64, 2.60, 2.62, 2.60, 2.56, 2.60, 2.62, 2.64    Spread = 0.08 grains, Average = 2.61

Then I filled the powder magazine to the top and did the same thing again.

2.58, 2.54, 2.62, 2.66, 2.56, 2.56, 2.56, 2.62, 2.52, 2.62      Spread = 0.14 grains, Average = 2.58

Now it has been my experience that with a freshly filled powder magazine, it takes a while for the powder to settle and get consistent weights, so just for the heck of it I dropped another 10 charges.

2.60, 2.66, 2.70, 2.70, 2.66, 2.64, 2.62, 2.68, 2.66, 2.70   Spread = 0.10 grains  Average = 2.664

So I guess you are right Art, there is a difference, and a full powder magazine seems to give slightly higher drop weights.

[ARTINCT]

Wow, great testing work on your part Bruce!
  
You are right that the powder when freshly poured into a magazine needs to settle.
Gently tapping the magazine with your finger, from top to bottom a few times will help accomplish this settling I would imagine.

Also, it has been my experience that when doing tests like this, that weighing aggregated throws help at the expense of understanding throw to throw variance.

For instance, do ten or more powder throws and weight the total sum of the ten throws.
So if you are aiming at 2.7 grains of something after ten throws you should have dispensed 27 grains (2.7 x 10)  This method is a little less fussy.  Also, by doing only one measurement vs. 10 you may eliminate weight error variance imposed by the scale which over 10 or more throws can add up.  It may be 6 of 1 or half a dozen of the other...  but it is easier.  On the other hand, the understanding of throw to throw variance is important to some extent in understanding the effect of using the Star reloader and how a specific behavior may have a correlation on outcome.
Again I think speed, overall smoothness and cadence may have an effect on outcome.  Also the condition of the cam bumps on the powder cam and how the charge bar vibrates on them (spring tension comes into play here) is a factor, how much I do not know....   

I applaud your work and data.  So thanks so much on that effort!

I wonder how varying machine operational speed has as an effect on throw weight?  I suspect that the vibration of the charge bar on the detents is very important to outcome.  The hypothesis being that a slowly operated cycle may not produce much charge bar vibration and the charge will be less settled.

Slightly changing the subject to that of how do I retrofit baffles into my baffle free powder magazines...

To retrofit my two plastic powder magazines with a baffle, I will be asking a machinist friend of mine to fashion a conical baffle out of aluminum (on a lathe) to a slightly less inside diameter than that of the tube.  I will ask him to cut a few slight recess grooves, much like those on a auto cylinder for rings.  Then using an appropriate sized rubber O ring(s) to fit the grooves it should make for a nice fit.  The trick will be to find O rings of the right size.

[ARTINCT]

Art,  I think there is some confusion about just what each of us is calling a baffle.   The Universal machine that I sold to you has its original factory baffle, the aluminum disk above the brass base.  Star did not offer any other baffle to my knowledge.

Bruce

Oh Jeepers!  before going any further I need to explain.  I am color blind.  And I really cannot tell or differentiate fine or subtle color / hue differences.   Bruce, You are correct Sir.   It appears that all of my Stars (including the 45ACP I got from you) do indeed have an ALUMINUM baffle situated directly atop the threaded brass magazine end.  So all of mine have a baffle.

However I posit that the location of the baffle as described may not be as effective as it could be IF it were located about 1 inch or more away or above the threaded brass magazine end thus providing a larger reservior of powder.