Inconsistent Powder Drops


Bruce.

I have recently purchased an MEC 600 Jr. I also got a Universal Charge Bar Model C/CS. This weekend I had the chance to use it for the first time. The round to round variation in powder weight is quite large. Do you know how I can get more uniformity?

Jonathan

Dear Jonathan,

I don’t think that the powder variation is due to the Universal Charge bar. I’ve used the Universal charge bars for many years and have never found them to be more or less accurate than ordinary bushings as far as consistent drop goes. The single station presses are “bumped” five times per shell during the loading cycle. This makes it vital to use the same technique and pace from shell to shell if you want powder consistency. Do make sure to lock the settings on your Universal bar with the little Allen key so that it doesn’t shift though that has not been a problem area on any of my Universals.

The first thing I’d do is to get a powder baffle. It fits between the powder bottle and the charge bar and evens the weight pressure on the powder.

http://www.midwayusa.com/eproductpage.exe/showproduct?saleitemid=393396

If that doesn’t cure it, try switching to a powder with a medium grain size. I’ve found that powders like 800X, with grains the size of pancakes, often meter poorly. I’ve also had trouble with very fine powders like Titewad because they seem to attract static electricity and that can cause inconsistent drops. No amount of dryer anti-static towels or grounding wires helped with the static when I tried those fixes.

Also make a point of keeping your powder bottle between 1/3 and 2/3 full. Not more. Not less.

Another thing- make sure that your powder bar is traveling fully to the end when you push it over. A partial throw will give you a partial charge.

If that doesn’t do it, I don’t have an answer for you. Come to think of it, I’ve got an RCBS Grand that doesn’t throw powder as consistently as I’d like.

If any of our readers has some ideas I’ve missed, I’d sure like to hear from you.

Best regards,
Bruce Buck
Shotgun Report’s Technoid

 

Advertisements
This entry was posted in Shotgun related and tagged . Bookmark the permalink.

3 Responses to Inconsistent Powder Drops

  1. Scooter123 says:

    First, I’ve been using Statistical Process Controls in manufacturing since the mid 1980’s. So I am quite familiar of Statistics and it’s value to a process such as dropping a charge of powder. I also do a Capability Study for every powder I use in reloading (Rifle, Pistol, and Shotgun). IMO the powder bottles for the MEC reloaders are poor designs and near worthless. I’m currently using Clay’s for reloading 12 gage Target/Sporting shotshells. I have run 3 separate Capability Studies on Clay’s and the results are miserable.

    Study 1 was the full loading cycle using the original component set. Problem One was that decapping station produced a HUGE variation in how hard the press was shook every time a cap was removed. Cause was the primers bassically “sticking” in the case by a very large variation. There is no solution for this and the Standard Deviation was a miserable poor 0.486 grains and the 3 Sigma Deviation was 1.46 grains. Folks that produces a loading range variation of +/- 1.46 grains or nearly a 3 grain range of variation for the standard 6 Sigma Standard used for SPC.

    Second study was done by decapping a batch of hulls with the Powder and Shot bottles on the workbench next to the press. So the loading cycle was Prime, Charge, and Crimp. As a result of this the press wasn’t being violently shook when a primer was “sticky” in the decapping station. This improved the Standard Deviation to 0.32 to the variation range was +/- 0.96 grains or a total range of variation of 1.92 grains.

    Third study was with a “baffle” and the results were revealing in that these baffles are noting but Sales Hype. This “baffle” basically had NO effect on the Standard deviation as this trial produced a Standard Deviation of 0.31. Folks don’t waste your money on these “baffles” because they don’t provide any benefit.

    BTW, I expect we will see reply’s where someone has checked a range or 10 charges and all of them were within +/- 0.3 grains and that is Statistically possible. However anyone with a few years using Statistics will state that this “low” degree of variation is an indicator of a much larger range of variation. What Statistics does is produce a “snapshot” of the total potential degree of variation if one were to do a much larger sample size. For 6 Sigma the total degree of variation can “capture the 1 in 3 million range of valuation. Meaning out of 3 million parts only one will measure outside the 6 sigma range. While that sounds a bit excessive in terms of an acceptable process today nearly every single automotive supplier is held to 6 Sigma tolerance. I can also tell you that if one of your parts supplied fails inspection or fails to assemble properly it turns into a Huge Mess with the customer demanding parts be quarantined and inspected by a third party inspection service.

    Bottomline is this. Until someone decides to design and build a Powder Bottle with a true Baffle as used in some Lyman and RCBS powder measures you can expect your thrown charges to vary by an unsafe and unacceptable amount. My process for reloading shotshells going forward will be to use the press to deprime, prime, tinsert the cup, load the shot, and Crimp. As for the Powder Bottle I won’t be using it, what I will be using is my RCBS Competition measure which will be mounted to a different bench than the press.

    Like

  2. Dan Kenny says:

    To Terry Cherry this make sense for me I’m good with it. I was trying to load for my daughter, Thanks

    Like

  3. Ted Cherry says:

    I believe that the ambient temperature and relative humidity has some affect on consistent powder drops. For those like myself, that accept +/- .5 (1/2) gr. as close enough, this is most likely not a factor, but for those that demand +/- .1 to .2 gr. consistency, they may try controlling temp. and humidity as best they can depending where they reload and if any controlling is even available. I use a UCB (universal charge bar) with a baffle, with either Hodgdon Int’l. or Alliant e3, and while accepting +/- .5 gr. I have no problems maintaining this drop variation, only difference being that at colder temperatures the drops seem to be more on the – side than the + side.

    Like

Leave a Comment

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Google+ photo

You are commenting using your Google+ account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s

This site uses Akismet to reduce spam. Learn how your comment data is processed.