BP volume to weight

[jtmattison]

I just had a moment of boredom so I went to the garage and measured a couple 100 grain by volume charges of Goex 2f. I weighed them on my powder scale and they both came out about 102 grains +/- a tenth of a grain. So, it seems a volumetric measure of BP is pretty much right on to weight. The couple grains difference can be attributed to my powder measure, how it's poured...etc.
So in conclusion I guess it wouldn't be all that beneficial to weigh charges for shooting. The volumetric measure is plenty accurate enough IMO.

I did an experiment a while back measuring several charges, tamping half and not tamping half. The charges that were poured and then leveled in the measure without tamping had much less deviation in weight than the tamped charges.

HD

 

[roundball]

I just had a moment of boredom so I went to the garage and measured a couple 100 grain by volume charges of Goex 2f. I weighed them on my powder scale and they both came out about 102 grains +/- a tenth of a grain. So, it seems a volumetric measure of BP is pretty much right on to weight. The couple grains difference can be attributed to my powder measure, how it's poured...etc.
So in conclusion I guess it wouldn't be all that beneficial to weigh charges for shooting. The volumetric measure is plenty accurate enough IMO.

I did an experiment a while back measuring several charges, tamping half and not tamping half. The charges that were poured and then leveled in the measure without tamping had much less deviation in weight than the tamped charges.

HD

Good to hear...I did pretty much the same thing a few years ago and had the same results.

And amazingly, in spite of a few whole grains variance one way or another from shot to shot, your rifle's accuracy doesn't switch back and forth between being a tack driver one time and a shotgun the next :grin:

I started out with TC's adjustable brass 50-120grn powder measure, then tried a few individual measures, ultimately scrapped them all and only use TC's adjustable measures...a 20-60 for the .40cal, and a 50-120 for everything else.

 

[mykeal]

So in conclusion I guess it wouldn't be all that beneficial to weigh charges for shooting. The volumetric measure is plenty accurate enough IMO.HD

I'm not sure what you are getting at.

What would it have mattered if there was a big difference between weight in grains and volume in grains? Pick a unit of measure, shoot varying amounts and pick the one which gives the smallest groups at the ranges you intend to shoot.

If you measure in the field before each shot, volume in grains is pretty much what you need to know. If you prepare charges beforehand and carry individual charges in separate containers to the field, either volume in grains or weight in grains is usable.

The important thing is to determine the best charge, whether in metric tons, cubic miles, grains volume, grains weight or whatever, and measure it consistently and somewhat accurately each time.

What am I missing?

The statement, "...a volumetric measure of BP is pretty much right on to weight." appears to be valid for 2f Goex; do you have data for any other brands or granulations?

 

[Rebel]

You missed the part at the beginning where he said he was Really Bored. :grin:

 

[mykeal]

You missed the part at the beginning where he said he was Really Bored. :grin:

Yup. You're right, I did. Oops. :redface:

 

[faw3]

"And amazingly, in spite of a few whole grains variance one way or another from shot to shot, your rifle's accuracy doesn't switch back and forth between being a tack driver one time and a shotgun the next" ya used the words the Bevel Bro's used in the NOV Muzz Blast , " volumetric measure of BP is pretty much right on to weight." appears to be valid for 2f Goex; do you have data for any other brands or granulations? " And I would ike to kow too now, I find it hard to belive 2/10 a gr would open a great gp open but they sure showed it done and they aren't just some clowns to laff off, if they say 2 gr's weight will open it up to like a shot gun maybe when I can get out of bed try some of my rifles again, now with 4f as main fuel I know it's very trickey by weight even ( a guy ran a add in back of Backwoodsmen for years till just a few back) he had got USA patent's for his set up with 4f anf PRB's useing the early CVA Mountain rifle ( I'll tell ya here dont even think about it now, I blew a hammer and chunk of barrel off a non USA barrel made one so I wouldnt trust any I dont guess) Oh ya the point of this I know it seems Ive shot 5 grs or so different and the ball still hit the same spot "about". so I'm ??????????? FRED :hatsoff:

 

[mike alexandre]

I think the whole point of this is to find out which is the most consistant for you, your powder and your gun. Some powders do not measure accurately from the drop tube, some do.
I agree that some rifles with either ball or bullet will put the hole in the same place.
The whole point of doing this is remove one more variable, if your shots and group are not as they should be then by having accurate loads you know you need to be looking for some else.

 

[Grenadier1758]

...the words the Bevel Bro's used in the NOV Muzz Blast , " volumetric measure of BP is pretty much right on to weight." appears to be valid for 2f Goex; do you have data for any other brands or granulations? "

I was really bored several years ago, so my other brands of powder are not presently available. At that time GOEX was right on for volume to weight. Elephant was about 10% heavier. I noticed more of a difference to be found in the markings on different powder measures. The most accurate for volume to GOEX was my measure from the Hawken Shop. So the word for consistency here is to only use the one measure when you get a load for accuracy, then don't change measures.

 

[faw3]

Don't know how but I've had the same 2 since around 1978 or 79, couldn't belive it when I thought about it. One is a made in the late 60s Im guessing when guys still thought 200 grs was the safe and thing to shoot and I guess for MST it was. :rotf: Then we all got dumb by laws and law sueeeeeeing! :grin: Fred :hatsoff:

 

[jtmattison]

So in conclusion I guess it wouldn't be all that beneficial to weigh charges for shooting. The volumetric measure is plenty accurate enough IMO.HD

I'm not sure what you are getting at.

What would it have mattered if there was a big difference between weight in grains and volume in grains? Pick a unit of measure, shoot varying amounts and pick the one which gives the smallest groups at the ranges you intend to shoot.

If you measure in the field before each shot, volume in grains is pretty much what you need to know. If you prepare charges beforehand and carry individual charges in separate containers to the field, either volume in grains or weight in grains is usable.

The important thing is to determine the best charge, whether in metric tons, cubic miles, grains volume, grains weight or whatever, and measure it consistently and somewhat accurately each time.

What am I missing?

The statement, "...a volumetric measure of BP is pretty much right on to weight." appears to be valid for 2f Goex; do you have data for any other brands or granulations?

I wasn't really getting at anything. I recall seeing where someone was shooting something like 87 grains of powder. I had to assume they were weighing their powder. So I figured I'd just see how close my volumetric measure was to actual weight of 2f Goex.
I was just bored and thought someone here might be interested to know my results.
I am very familiar with working up loads. I do it with a volumetric measure and I see no need to weigh my powder. I was just curious.
I wasn't trying to start anything :surrender:

HD

 

[mykeal]

...I was just curious.
I wasn't trying to start anything :surrender:

HD

I understand. Rebel suggested I missed your opening statement, and indeed, I did. Makes all the difference. I'll try to do better in the future. :redface:

 

[Dave Rosenthal]

Thanks for taking the time to check this out...I remember seeing mention of this very same idea on another thread a short while back.

It's interesting to note how accurate your measurements actually are...less than 2% variation from charge to charge! So that means that if you threw 50 grain charges, you might be off by only 1 grain!

I always pre-measure all of my charges and put them into individual tubes, and then put the tubes into several cigar boxes, a different box for each amount of powder. This keeps everything straight when I'm shooting at the range, especially during a competition! I use a powder measure that's good for 5-120 grains of powder.

When using the powder measure, I tap the side of the measure several times to settle the charge, then add more powder and tap it again a few times to top it off. Then I twist the spout into battery and pour the powder into each little tube without spilling a single powder flake as I pour the charge into the tube. I do get some powder to fall off the measure as I twist the spout, but it's all caught by the paper towel that I place on the kitchen table where I work. I guess that I'm a little A-R about my charges, but the results speak for themselves.

Just goes to show you that doing everything the same all of the time does work indeed!

Dave

 

[jtmattison]

When using the powder measure, I tap the side of the measure several times to settle the charge, then add more powder and tap it again a few times to top it off.

In a previous experiment I did that as well as measured charges without tapping the powder measure. There was much less deviation in charge weight when the measure was not tapped.

HD

 

[Dave Rosenthal]

Very Interesting :hmm: , I'll have to borrow my Brother's powder scale and do the test myself. He's a centerfire shooter/reloader.

Thanks for the clarification!

Dave

 

[Stumpkiller]

I have an adjustable measure I got from Dixie (says "Made in Italy") that will throw a 120 grain 2Fg charge at the "100" setting. As long as your measure is calibrated there isn't much reason to worry about it. If it's off as much as that one it could get you into trouble.

 

[Dave Rosenthal]

Thanks, I did do a rough job at calibration by pouring 2 fifty grain charges back into the measure just to see if the thing worked near the max setting. It was right on at the 100 setting, so I guess that I'm O-K. Bought my measure from Chuck Dixon of Dixon Muzzleloading Shop in Kempton, PA. I think it was made by RMC, which is short for Rightnour Manufacturing Co., also imported from PA!

Dave

 

[longcruise]

smokin .50 Said:
When using the powder measure, I tap the side of the measure several times to settle the charge, then add more powder and tap it again a few times to top it off.




In a previous experiment I did that as well as measured charges without tapping the powder measure. There was much less deviation in charge weight when the measure was not tapped. With this measure i didn't have to add more powder after tapping because the small mound of powder above the top edge of the measure never settled below the top of the measure.

HD

I got the opposite results with the same experiment.

Here are my results of pouring charges of Elephant ffg from a funnel top style adjustable powder measure set at 80 grains of volume. First I poured and weighed 10 without tapping the measure and then another ten received three sharp flicks of the finger after pouring and before shearing with the funnel spout.

Here's what I came up with

First, the 10 that were poured and sheared without tapping the measure

93.5
94.1
93.2
92.5
92.8
93.6
94.0
92.8
93.5
92.2

93.2 Average Weight
.63 Standard Deviation
1.9 Extreme Spread

Next, the ten that were tapped and then sheared

94.3
94.2
93.5
93.9
93.8
94.1
94.1
94.0
94.1
94.3

94.0 Average Weight
.25 Standard Deviation
.8 Extreme Spread

Here is another experiment that I did. This was meant to show up the differences between the actual weights of powders when thrown from an identical volumetric setting

BP Weight Comparisons

From an RCBS measure at an arbitrary setting.

Graf 3f
55.9
55.5
55.5
55.3
-------
55.55

Goex 2f
51.1
51.7
51.3
51.4
-------
51.37

Goex 3f
52.2
52.1
52.5
52.2
--------
52.25

Elephant 2f
60.2
60.4
60.4
60.1
---------
60.27

Swiss 1.5f
55.9
56.1
56.4
56.2
------
56.15

Swiss 2f
57.4
57.2
57.2
57.4
-------
57.30

Pyrodex RS
37.0
37.1
37.5
36.8
-------
37.10

Here is another experiment I did at the range over a chronograph.

Average velocities for various powders with charges thrown from 50 grain volumetric measure. and shooting a .530 patched ball from a 32" .54 caliber barrel



Graf 3f

1405
1388
1370
1391
1396
Avg 1390


Elephant 2f

1135
1208
1215
1215
1238
Avg 1201


Swiss 2f

1546
1531
1574
1558
Avg 1552


Goex 2f

1349
1362
1376
Avg 1362


Goex 3f

1469
1516
Avg 1492 These two velocities were the only ones obtainable due to bright sun and erratic chrono behaviour

Pyrodex RS

1494 Only one good reading due to sun on chrono

I started this experiment with overcast skys and then later the sun hit me at a sharp angle which often causes my chrono to act up. I'd like to repeat this on a day that is completely overcast.

Notice that the densest powder (elephant) shot with the slowest velocities!! :shocked2:

It has been correctly pointed out that my figures are only relevant to the particular lot of powder for each brand. The Elephant, for example was a very old lot. Others have found some variations in Goex lot to lot results and those same variations probably show up in the other brands as well.

Here's what I took away from these figures:

1. Always use the same powder measure for any given gun. If you make or acquire a new measure, calibrate it off the old one.

2. If you want less variation in your charges, tap the measure in some consistent and repeatable manner.

3. Once you settle on a powder brand stick with it and remember that your next purchase of that same powder may be from a different lot and may vary somewhat.

4. Your fabulous match load off xx grains of x?x?x? brand of powder may fall apart completely if you change to a brand of powder that varies as much as some of those variations seen above you may not get the same results by pouring the same charge from the same measure as used with the previous powder.

5. Guys who find extreme differences in accuracy from charges varied by one or two grains are looking at an extremely small sample (one three shot group is the infamous standard of many ) or they may be careful observers shooting at extremely long ranges, eg., 500 to 1000 yards.

6. If there is a sweet spot with any given powder and charge, recovering that sweet spot when changing powder lot or brand could be based upon arriving at a charge giving the same velocity of the previous sweet spot. Or, lacking a chronograph, the exact same POI with the identical POA as with the previous accurate load. (Total disclaimer! This is a totally untested theory coming from a guy who was certain that not tapping a measure would be the most accurate method of powder measure..... until I did the above bench top experiment )

7. All this hair splitting could be nothing but an irritation to those who just like to pick up their guns and go shoot. So, if you are one of those, then ignore this BS and pick up a gun and go have a blast!!

 

[jtmattison]

:snore: Just kidding :haha:

That's some great information. Thank you for taking the time to share it.
It's interesting you had the opposite results with tapping the powder measure. I tapped mine the same way every time but came up with more deviation than just pouring and cutting with the spout

I was measuring Goex 3f at the time. My weight experiment this time was done with Goex 2f. Maybe 3f settles differently due to granulation size :hmm:

HD

 

[Dave Rosenthal]

I continue to win competitions doing it your way, so for now I think that I'll continue tapping the side of the powder measure to settle the powder and then top it off and tap a second time. Then I'll twist the funnel top and apply my tubes to receive the charge.

Short of actually weighing each charge that I throw (don't have a scale), I think that is the only way to reduce the variable to obtain consistancy and tighter groups. I haven't done the type of testing that you have, so I'm glad to take your word for it!

Dave

 

[longcruise]

Just kidding

Heh heh, yes, but not entirely I'm sure!!

I shoulda put observation #7 at the beginning of the post! :rotf: