Priming Powder

[Frizzen]

Larry, I just sent you a PM

[Larry Pletcher]

Pletch,
I have had some private messages suggesting I talk you into looking at that moisture pickup thing from the aspect of lock timing.

If you remember way back we talked about your finding that the function of the pan powder represented roughly 60% of the lock time while the mechanical end of it was about 40% of the lock time.
(snipped)
So there are a few out there who wonder what this moisture increase in a pan powder would do to lock time when it comes to firing the gun.
Bill K.

Bill,
I'm thinking this idea through, and then I want to pick your brain a bit.  My first reaction is that I think I can do it.  Need to put together more ideas.
Regards,
Pletch

[Mad Monk]

Pletch,
I have had some private messages suggesting I talk you into looking at that moisture pickup thing from the aspect of lock timing.

If you remember way back we talked about your finding that the function of the pan powder represented roughly 60% of the lock time while the mechanical end of it was about 40% of the lock time.
(snipped)
So there are a few out there who wonder what this moisture increase in a pan powder would do to lock time when it comes to firing the gun.
Bill K.

Bill,
I'm thinking this idea through, and then I want to pick your brain a bit.  My first reaction is that I think I can do it.  Need to put together more ideas.
Regards,
Pletch

It would be no big deal.  3F and 4F powder will reach an equilibrium with the air in 15 to 30 minutes.

Easiest approach would be to simply allow some pan powder to adjust to specific levels of Relative Humidity.  When I would measure the actual numerical percent gain or loss I made little heavy duty aluminum foil pans that fit on my Lyman beam balance loading scale.  The just watched the weight go up and down as the R.H. changed.

With a test like you would run it would be nice to see how much the lock time is slowed as the humidity goes up.  Most shooters could not relate directly to measured amounts of moisture changes in the powder.  But given data relating to specific R.H. percentages might be meaningful relative to how often one might have to change pan powder that gets damp in the pan.

Cow knees are sold to keep rain off the lock and away from the powder in the pan.  I suspect that yes indeed they will keep rainwater out of the pan but offer little protection against moisture in the form of R.H. with the air under the cow knee but over the lock.  Would the air trapped under the cow knee contain enough water to effect the performance of the powder in the pan.

Bill K.

[Larry Pletcher]

Thanks, Bill,
What was going through my mind was to weigh out 100 grains of powder and expose it to the air.  After a period of time weigh it again to see what the exposure did to the weight.  For instance if the 100 grains became 102 grains after exposure, can we say that the 2 grain increase is water?  (If I remember correctly, powder from the can is probably close to .5% moisture.)  Having a weight would give a relative way to categorize the testing.  For instance one could say, " We compared priming from the can to powder whose weight increased 2% when exposed to air."

Perhaps this could be done a couple of times with exposures to varying RH.

I'm just tossing out ideas here and open to suggestions.
Regards,
Pletch

[Daryl]

Weighing out the powder would have to be done in a controlled (known) humidity environment, me thinks, prior to it's being exposed to higher humidity. Not an easy task for positive results perhaps? I'm not sure a beam scale will give true readings - maybe it will.  The sensitivity might not be fine enough, at 1/10th grain weight, plus the 1/10gr. accuracy error inherent in scales.

[Mad Monk]

Weighing out the powder would have to be done in a controlled (known) humidity environment, me thinks, prior to it's being exposed to higher humidity. Not an easy task for positive results perhaps? I'm not sure a beam scale will give true readings - maybe it will.  The sensitivity might not be fine enough, at 1/10th grain weight, plus the 1/10gr. accuracy error inherent in scales.

My humidity chamber was my roofed over deck attached to the back of the house.  Scale set up on a table.  Poured powder from the can into the foil pan on the scale.  I used a Radio Shack weather station with digital read out to see what the R.H. was at the time.  Checked the accuracy of the weather station against the data shown at the time on the local weather station.  The Radio Shack device was very close to what the weather station 2 miles away was giving the TV.

I put rougly 37 years in lab work.  The simple beam scale is accurate when set up properly.  If 100 grains of powder picked up 1.5 grains of weight it is a 1.5% increase.  I used 500 grains of powder to increase accuracy.  The simple beam scale is as good, or better than most of the electronic scales now being sold for reloading.   The Mettler balances I worked with it the labs required frequent calibration and adjustment.  The only thing you have to worry about with a beam scale is getting it level and zeroed.

Bill K.

[Daryl]

As to humidity effecting modern stuff, the BR shooters usually load for volume, and disregard humidity - their Harel scales are set at home and they continue to use the same volume, regardless of it's weight.  Some take a step further, and increase or decrease loads depending on the atmostpheric conditions - I don't know if that means merely pressure or humidity as well. Of course, this does nothing for the 'task' at hand, in measuring primer speed woth different humidity.

[The other DWS]

I suspect that humidity effect on weight is why most of the experienced BP shooters across the board load by volume rather than strictly by weight.   I'm interested in how the absorbed humidity impacts ignition and if more humid powder has less or more "power"  (I assume calories or something relative to burn time) than a drier one.

I'd think that a powder charge in a gun barrel corked up with a patched or wadded ball would be fairly proof against weather except for the prime charge and what very little might enter through the touch hole.  yet I have read historical documents in which troops were told to draw their charges and reload prior to battle.  And then there are all the military references to having to stop a march to ''dry the powder" though that might be a reflection of paper wrapped musket cartridges in not-so-weathertight cartridge boxes needing to be spread out in the sun to dry.

[Larry Pletcher]

The experiments are beginning to pile up.  Steve and I have a number of possibilities.  We need to begin a list and to schedule our time.  He has a strange work schedule, and I am bogged down right now in preparing our entry in the Shell Eco Marathon held in Houston next week.  We may get at this in April. 

Kerry Neilson here on ALR has some amazing ideas for vents based on air flow studies from high performance engines.  Some much to learn and so little time.

Bill, I will send you a PM when I get caught up.

Regards,
Pletch

[Dphariss]

I also agree from experience that Swiss Null  doesn't draw moisture any quicker than Goex 4F. However.....perhaps Monk could explain why,when hunting and you fire a shot that the next pan full or more will draw moisture much quicker than before the first shot. Perhaps something left in the pan after firing that 1st???
 Or just condensation from firing a cold gun (Pa. winter temps)

Growing up in Iowa the FOULING will literally liquify in just a few minutes in the open air. So the pan, frizzen and area around the vent have to be wiped clean or the fouling will absorb moisture from the air and wet the powder it comes in contact with. Running a pipe cleaner or such through the vent before loading is a good idea too.

Dan

[Daryl]

We-too get the pan-full-of-water deal, but not often- thanfully.  At Hefley Creek Rondy last fall, the first week had the relative humidity around 6%.