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Uniflow Powder Measure

Discussion in 'Handloading and Reloading' started by traveling1253, Dec 31, 2010.

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  1. traveling1253

    traveling1253 Member

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    I have the RCBS Uniflow Powder Measure that came with the RCBS master kit. Put my first few rounds together last night and found that the metering required constant fiddling. I followed the instructions carefully, dissasembled and cleaned all the oil/rust preventative out of the workings then ran a bunch of powder through at max setting before first use. In the instructions there is mention of an optional small measuring screw assembly, would that aid in getting consistent powder throws with the small amounts needed when reloading .40 S&W pistol rounds?
    I loaded just a few testing rounds using once fired Winchester brass, CCI #500 SPP, 180gr Berry's RS and Hodgdon Longshot powder. Did 10 each using the 6.5gr starting charge listed in Hodgdon's loading data 6.7,6.9,7.1,7.3 I ended up weighing almost every other charge. The charges were not off by alot but would be just slightly above or below the zero mark on my RCBS scale(less than .1gr either way) Is that just the nature of the equipment that needs time to wear in or type of powder( tiny flakes ) that was causing this? I tried my best to operate the handle smoothly and consistent and I guess I was expecting dead-on measurements every time. Do some brands of powder measure out better than others?

    Thanks
     
  2. hydraulicman

    hydraulicman Member

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    did you cycle a pound of powder threw the measure before use?

    I have a uniflow and it's about as dead on as it gets with ball powder. it's a great measure.

    Practice a bit with it and if you want get the pistol drum.

    happy loading you have some great gear
     
  3. Jesse Heywood

    Jesse Heywood Member

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    Powder dispensers need baffles. RCBS will sell you one. It's my opinion that the baffle should be part of the dispenser package.

    Here are plans to make your own.
    http://www.thehighroad.org/attachment.php?attachmentid=78980&d=1211856964

    The small metering screw is also a necessity when dropping charges under 10 grains. If the baffle doesn't get you close enough, you will need to throw in for the small measure.
     
  4. X-Rap

    X-Rap Member

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    Yep get the baffle and try to stick with ball powder.
     
  5. sweater914

    sweater914 Member

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    I had similiar experiences when my Uniflow was new. It took some breaking in before things settled down. My RCBS 1010 scale also had an interesting quark, but that's another matter.

    Here are some techinques you can use for more consistent charges.

    1. Make sure the hopper stays 1/2 to 3/4 full. Powder has a tendency to settle as you throw charges, keeping the hopper topped off will allow the fresh powder you put in settle before it gets to the measure.

    2. The first time you fill the hopper, throw 20-25 charges before you take one for measure (see #1).

    3. After you make a change to the adjustment screw, even small changes, a minimum of 10 charges before you take one for measure.

    4. Spherical and flake powders work best in the Uniflow. But realize the limitations of the equipment, we're trying to use a volume measure to weigh a solid. Stick powders are an absolute pain in the Uniflow, if the handle sticks during the throw the charge will be off. It takes at least one more throw to return an accurate charge. I've stopped using stick powders in the Uniflow and prefer to hand measure.

    If you're using a balance beam scale make sure it's away from fans, air ducts, etc. Breathing heavily on the scale will effect the reading, until it settles down. My 1010 scale has a dead spot, small but noticable, I tap my bench near the scale the beam will move and settle at a new location. As you can imagine until I found the issue it drove me nuts.
     
  6. BADUNAME37

    BADUNAME37 Member

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    I have the RCBS bench-mounted powder measure, I bought a baffle for it which is a piece of bent tin - round with two V-notches in it.

    Anyway, I believe I have the larger screw, and I bought the (larger) Micrometer kit.

    I load for .380 Auto and it throws consistent loads every time - even as small as a load for the .380! In fact, I can switch powders and go load other calibers and come back, clean out all the other powder and dial-in the .380 load on the mic and it will be SPOT-ON, most every time! If any changes are needed, they are so very miniscule, that the fine-tuning may not even be necessary at all - as my 5-0-5 RCBS scale will be off by maybe 1/16" (1/8” at most) from center! Being that close, I could just throw all the charges, however, being as anal as I am, I do fine-tune as needed.

    I just went to the basement and got my .380 load recipes (these are for illustrative purposes only and must not be used unless each load has been worked up from minimum - depending on bullet used, primer used, etc.):
    Red Dot - 2.8 grains; micrometer powder measure: 38
    Power Pistol - 4.6 grains; micrometer powder measure: 30

    After using it with and without the baffle, I have found that the baffle is not really necessary. If you are throwing really small loads, just fill the hopper an inch or two, instead of chucker-block full.

    One thing I am persistent at is making sure each cycle of the rotor hits (or knocks) at each end - I'm not talking about hammering on it, but I am saying a definite "knock"-sound at the bottom and top of the throw-cycle.
    IIRC, the instructions tell you this!

    The way mine is set up, the weight of the micrometer makes the rotor opening in line with the hopper at all times and the micrometer is in the down position due to gravity. When I lift the micrometer to the top of the cycle (using either the micrometer or the handle on the right side of the rotor), the rotor hole closes from the upper hopper and opens to the drop tube down to the empty case. When I bring it down, I bring it down with about the exact same "knock" I used when I brought it up which I think helps to settle the powder, not only in the hopper, but also into the rotor hole - so each load is uniform. Whichever way you do it, you must be doing it the same every single time, or your powder dropped may be inconsistent.

    I did find that it took some practice, throwing a lot of loads directly into my scale pan, then placing the pan onto the scale to see how I am doing, then dropping the pan powder back into the top of the hopper. After a while, you will get just the right “feel” for the proper knock at both the top and bottom of the cycle for your particular powder measure!
     
  7. cfullgraf

    cfullgraf Member

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    I find the powder baffle is helpful. Make sure the openings in the baffle are 90 degrees to the axis of the rotor drum.

    I also find the small cavity is helpful for small charges.

    Consistent operation is also helpful. Try to get into a rhythm and operate the lever the same way and speed each time.

    As others have said, you need to throw a number of charges after making an adjustment. It helps if you can make the adjustment without any powder in the cavity. Kind of a "rub your tommy, pat your head" activity but has less effect on the powder column above the rotor drum.

    Make sure the measure is clean of any preservative lubricant. Also, wiping down the insides with an anti-static dryer sheet helps prevent static in the measure until a layer of material from the powder, I think it is a graphite like compound, has built up inside the measure. Running a bunch of powder through the measure can substitute for the dryer sheets but takes more time.

    Hope this helps.
     
  8. HOWARD J

    HOWARD J Member

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    When I lift the handle up I knock it twice & when I bring it down I knock it twice----you must use the same pressure each time---after a while you will get used to it.
    Good luck
     
  9. traveling1253

    traveling1253 Member

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    Ok, so I need to get the optional small metering screw assembly PN 98902, the baffle PN 90225, wipe the insides of the unit with dryer sheets and practice/perfect my technique. Seems there is no end to the madness in this handloading business.:banghead:

    Thanks for the help
     
  10. JimKirk

    JimKirk Member

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    I have used my Uniflow for charges down to 5 grains with the large cavity with out any problem. If you are getting the accuracy within .1 grains as stated... then you are getting acceptable charge weight.

    The rotor has to wear itself to a "fit" in the frame.... give it some time to do so.

    If you are using charges so close to maximum that .1 grains will make or break .... then you need to back off the charge some.... otherwise .1 grain will never be noticed and is probably as good as factory standards for charges.

    If you'd like to see some large variations in charges ....try some 800X powder!

    If you have the impression that you will get an exact weight charge every time you throw one .... then you have been mislead. Tolerances are part of reloading just like everything else in this world. Just keep them small !!

    Jimmy K
     
  11. jeepmor

    jeepmor Member

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    I agree with Howard here, you need to be consistent in the way you operate your powder measure. I've noticed I can vary my charges just by varying how I crank on that little lever. Be consistent here and you will be fine without all the fancy upgrades to the measure. I've never tampered with mine and it throws to 0.1 grain toleerance no matter where I set. 9mm Luger all the way up to 300WSM.

    I do cycle nearly a full hopper through of a new powder through it back into it's container before starting a new batch just to get it dialed quicker. I probably don't need too, but it's just another thing I do in my reloading habits to be consistent.
     
  12. R.W.Dale

    R.W.Dale Member

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    I've noted that one thing that makes for much more consistent throws is to disregard the instructions and assemble the measure arm so that it dumps on the downstroke of the handle.

    This will allow you to operate the measure with a bit more authority that will facilitate clean unimpeded granule cutting neccacary for extruded powders.

    With the above methods my uniflow will meter big ol Lincoln log lookin imr5010 with as much accuracy as my scales will measure.


    Tapatalk post via IPhone.
     
  13. PowderKeg

    PowderKeg Member

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    Yeah well, it does help if you have a little OCD in you....

    I've got two Uniflows, one each large and small with the mic screws and baffles. The mics and baffles really do make a difference in helping keep very consistent charges. I found I would tend to unintentionally tweak the charge weight whenever I tightened down on the standard screws.

    My "ritual" for minor adjustments prior to filling cases is to adjust, tighten, throw a minimum of three charges back into the hopper, weigh the 4th, and repeat until the desired charge is reached. Then I'll throw and weigh 3 or so in a row to be confident that the charge is staying consistent. I check weight on @ every 10th or so throw, and randomly pull a few cases from the block to check after every 50. If I step away from throwing powder for any length of time, when I start back I'll throw a minimum of 3 back into the hopper and check weigh the 4th before continuing on.

    Initial major adjustments get 8 or more charges thrown back in before weighing, then the minor adjustment ritual starts.

    A steady and consistent technique in lifting and dropping the handle/mic helps too - if my "lift" feels off, or slips or hesitates a little, that charge goes back in the hopper, along with the next one. Also keep the hopper at no less than 1/3 full (above the baffle).

    My Uniflows have shown to be very consistent when I follow my ritual, even with stick powders, although I haven't used anything really big, and I do toss more stick charges back due to sticky "off" throws. I once considered buying one of the higher dollar Redding measures, but decided there's really nothing wrong with what I'm running now.

    Oh yeah, I keep a used dryer sheet handy for hopper wipe-downs - really helps alot.
     
    Last edited: Dec 31, 2010
  14. Joatmon

    Joatmon Member

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    +1 on the drier sheet. Around here with the furnace running for 6 months solid the static buildup on stuff is impressive. I see powder sticking to the sides of the hopper, drop tube, anything plastic. I tear off a strip and hang it in the hopper, put the lid on so that it does not work down into the rotor, and get to it. Saw this tip in an old reloading book (ABC's?). Probably a Dean Grenell original. It works though.
     
  15. cfullgraf

    cfullgraf Member

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    I use soft, easy strokes with all my measures including the Uniflow. I try not to disturb the powder column as much as possible. The other method of rapping the measure at the top and/or bottom of the stroke also works. As said, be consistent. Find the method that works for you.

    I throw the powder charge on the up stroke of the handle, but the down stroke might be easier to be more consistent. I like the adjuster in the front of the measure.

    As an aside, all of my powder measures are mounted on floor stands separate from the press. Operation of the press does not vibrate the powder measure and affect the density of the powder column. Maybe overkill and not necessary, but it makes me happy.

    I can run my powder in my Uniflow down to the level of the baffle with no changes in consistency of the powder charge. I do that when I am trying to run out a canister of powder. I am not comfortable doing that and generally check weigh the charges more frequently. I usually top off the measure when it gets to an inch or two of the baffle.

    Another aside, I have three powder measures set up for different range of powder charges. A Midway Indispensable measure for large rifles such as the 30-06, the Uniflow for small rifles such as 223 Remington, and a Redding 10-X for handgun. The hopper size and drum cavity are chosen for the range of charges to be thrown.

    A year ago I bought my first progressive and am going through some growing pains with the new powder measure.

    Multiple powder measures are one of the benefits of reloading for 30 years and not getting rid of any equipment!
     
  16. R.W.Dale

    R.W.Dale Member

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    Just to clarify the metering stem on my downstroke dumping uniflow is still in the front. The handle is what's reversed.

    I also do not have a baffle for mine. Instead I fill the measure with a funnel that I leave on top of the hopper partially filled, that way the amount of powder pressing down on the chamber remains constant [​IMG]


    Tapatalk post via IPhone.
     
  17. ranger335v

    ranger335v Member

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    "In the instructions there is mention of an optional small measuring screw assembly, would that aid in getting consistent powder throws with the small amounts needed when reloading .40 S&W pistol rounds?....
    The charges were not off by alot but would be just slightly above or below the zero mark on my RCBS scale(less than .1gr either way)"


    On the small metering cavity for handguns, generally, yes; that's why they make it. But few precision rifles will ever notice a charge variation of +/- .1 gr and no handguns at all; I know of no one who weighs charges for handgun stuff.
     
  18. rfwobbly

    rfwobbly Member

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    Mr 1253 -
    Welcome back. I answered this question so many times I finally just put it on my hard drive. Some of the info presented has been answered before, so please forgive.

    Powder Measure Tips

    • First and foremost should be a sturdy powder measure (PM) stand that holds your PM about 2 inch above the table and extends the outlet about 3 inches away from the post. You can buy these stands from RCBS and Lyman, or you can build one from wood scraps in your shop. You'll want the base to be plenty heavy so that it's not inclined to jump around, and the stand to be solid so that the PM doesn't wave around like a flag on a pole.

    • Accurate measurement of powder depends on several things; one of these is consistent powder density. So when measuring powder I use a technique called "knock-knock". Whenever the micrometer adjuster reaches either end of the stroke I simply hit the stop twice. All this vibration gets the powder to sift down to a constant density so that with each throw, the contents of the PM chamber are more consistent. And therefore the weights are more consistent. So when you operate the PM, you raise the handle and hit the stop twice (knock-knock), and then you lower the handle to dump and hit the stop twice (knock-knock). This may take some practice on your part.

    • Never use the first 10 "dumps" from the PM. Simply put them back into the top of the hopper. The first dumps out of the PM simply haven't shaken down enough to become a consistent density.

    • These PMs are also helped by a "baffle". Explanation and design attached. We're talking 5 minutes with scissors and a beer can. The most enjoyable part is emptying the can.

    • If you ever need to lube your measure, use only powdered graphite. If you use your PM often enough, the graphite on the gunpowder (the gray coating is graphite) will self-lube the measure for you.

    • Another tip is to get (or make) a "reloading tray" ( HERE ). As you prime your cases, put them mouth-up into the tray. When you have a goodly number, say 40-50, then dump powder into all of them in a single session. That way you get very good at knock-knock. AND you can take a bright light and inspect all the cases for equal powder height.

    • Powder measures, such as the Uniflow have a large and small rotor. You must match the large rotor to rifle loads and the small rotor to pistol loads.

    • Finally, don't ever leave powder in the hopper. Always put it back in the can. The acid in the powder will etch the plastic cylinder pretty badly. The gray color is a natural consequence of using gun powder. Nothing you can do about that except to convert to a glass hopper.

    I've also attached the plans for the home-made powder baffle.

    Hope this helps! ;)
     

    Attached Files:

    Last edited: Dec 31, 2010
  19. oneounceload

    oneounceload member

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    Have the handle down so it drops when you lower the handle - I "knock" it on the way up, keep the measure fairly constant as to volume and it has worked great for loads from 2.5 grains to 65 grains without issues
     
  20. cheygriz

    cheygriz Member

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    Get the pistol metering chamber, and develop a consistent operation of the handle, and your problems will be solved. Your measure is one of the best made. :)
     
  21. JimKirk

    JimKirk Member

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    Another fan of the handle down/powder dump method of setup.

    I called RCBS and talked to several of their techs who stated that is the way it is supposed to be set up.... got wonder why the directions and photos in the directions show it different!

    My method of operation is ...smooth up ...smooth down ... no bumps ...no bangs ... to each his own though!

    Jimmy K
     
    Last edited: Jan 1, 2011
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  22. Seedtick

    Seedtick Member

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  23. traveling1253

    traveling1253 Member

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    Thanks for the help, I was using the thing wrong. I had the handle wrong so the measuring "cup" was up with the handle in the down position. Switched it around so the "cup" is in the dump position with the handle down. Also wiped the hopper with a dryer sheet. Filled the hopper about 3/4 full and started throwing charges. Operated the handle like I was before with a soft clunk at top and bottom of the stroke. Must have thrown 20+ charges in a row weighing each one and returning the charge to the hopper. Dead-on consistent each time. I do plan on trying the home made baffle as well, seems like the right thing to do. May look into the optional small measure as well for when I try some other powders with smaller charge weights than the 6.5gr-8gr called for in Hodgdon's Longshot data.

    Thanks again
     
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