Powder metering problem

[Questor]

I was loading some ammo with Varget this weekend while it was quite humid. I used my RCBS powder measure and Varget powder. About 2 percent of the rounds (out of 650 rounds) had a strange metering problem. This was for .223 and .270.  

The bad loads would drop all but about three grains of powder into the first case, then the next case would be loaded with the intended charge,  plus the powder that was not dropped in the first case.

In the .223s this was nothing more than a nuisance because the powder was right into the neck. It was a bigger problem with the .270 because the case is not filled.  Moreover, the variation was slight enough so that it was difficult to see the difference with a visual inspection.

(I was using the appropriate drop tubes.)

Fortunately I caught the problem.

I don't know if this is a problem with the powder, or the fact that is had been raining for days and was very humid.  

Have you ever encountered anything like this?  I have never known this to occur. I have used similar powders, like RL15, IMR4198, and H4831SC and never had this occur.

[Mikey]

Questor:  I've had problems like that on humid days or days when it was so hot that the air was thick.  But, years ago I developed a technique to assure that all the powder dropped into the case.  

Now, I have both a Dillon 550B as well as an older Rock Crusher.  I have an old Lyman powder measure that is probably older than I am and the technique I use is as follows - I double tap everything in the powder dispensing process.  That means that when I drop the handle on the powder measure to fill the interal cavity with powder, I let the handle drop twice (or tap it twice) to make certain the cavity is both filled and 'tamped'.  Then, when I dispense the powder to the case, I double tap the handle against the body of the measure to make certain everything drops out.  That seems to work for me even when it is really hot and humid.  

I have found that once I get the powder measure regulated to as close to the charge I want as it will throw, I will be only .1 - .2 grains weight off on any charge I randomly measure, which is pretty ok for just 'fun fodder'.  For hunting or carry stuff, I measure out each charge.  HTH.  Mikey.

[Rmouleart]

Your best bet is to have a humidifier set up where you are reloading, this will also keep you stuff from rusting up;) Aim small hit small. RAMbo.

[PAShooter]

I'll second Mikey's suggestion, I have a RCBS powder measure, and I always double tap, especially with the extruded powders.