Jeff, this is good information, but can you describe your procedure for measuring VOLUMETRIC charges? do you just throw, pour, scoop, tap, scrape off level, etc,?
Any information is good information, but 2 of anything does not give enough information as far as a statistical sample size, per Statistical Process Control and Statistical Problem Solving.
What small amount of information you have does at least let us look in the window, and supports what I discovered back in 2008, and have been saying for the last 11+ years concerning Blackhorn 209. Not without a lot of protest, if you haven't noticed.
There are several other factors, both that you can control, and those you cannot. Storage by both the distributor and consumer, humidity, temperature, lighting (natural), age, seal on container, opened container vs all factory sealed containers, obviously Lot #'s, just to name a few.
Chart above shows avg velocity bye weight per 3 lots 165 fps difference
I got
175 FPS Extreme Spread from your
WEIGHED charges across the 3 lot numbers.
I got
61 FPS Extreme Spread from your
VOLUME charges across the 3 lot numbers.
Quite a difference!
Guess my data is confusing.
Lot 30 was shot at 120v and 84w
Lot 31 was shot at 120v and 84w
Lot32 was shot at 120v and 84w
Left side of photo says lot 30v this was 120 volume also 30w this was 84 gr weight.
So info is on sheet
84gr wt
Lot30 2316
Lot31. 2217
Lot32. 2155
The only thing that confused me, after I figured out the method to the madness, was the top numbers above the line that were also VOLUME charges from lot #30 with cold bore beside them. You didn't also list a WEIGHT charge, so I didn't use those numbers, since you had lot #30 with all the others below the line. The numbers also seemed to conflict with the other numbers from the same lot?
30v is lot 30 volume 120
30w is lot 30 weight 84
OK, without getting to technical, I used your information of all 3 Lot Numbers to show something that everyone should be able to understand.
If you were to venture from one lot to another, blindly without a Chronograph, for both VOLUME vs WEIGHT.
Using 120 grains VOLUME = 84 grains WEIGHT, per Western Powders.
120 gr VOLUME MEASURED CHARGES, FPS, Total, High, Low, Ave, Extreme Spread, for all 3 Lots.
Lot #30
2280 H
2219
Lot #31
2238
2219 L
Lot #32
2221
2243
_______
13, 420 / 6
= 2236.6 AVE
2280. High
2219. Low
2236.6. Average
61 FPS Extreme Spread (VOLUME)
84 gr WEIGHT MEASURED CHARGES, FPS, Total, High, Low, Ave, Extreme Spread, for all 3 Lots.
Lot #30
2331 H
2301
Lot #31
2211
2224
Lot #32
2158
2152 L
________
13,377 / 6
= 2229.5 AVE
2231 High
2152 Low
2229.5 Average
179 FPS Extreme Spread (WEIGHT)
I think you guys are starting to figure out what I've been saying, and getting a whole lotta flack for for years. That's OK, I grew up on a farm and have very thick skin.
If you WEIGH your charges, you better have a chronograph, because every time you change Lot Numbers, you need to figure out what WEIGHT charge gives you the velocity you desire for you chosen bullet. It will change each and every LOT.
So, I guess it's safe to say, at least from your small sample sizes, that there is still variation from one Lot to another Lot, even after Lot #30. Even more so if you WEIGH your charges.
There is more to, "It's Always The Same VOLUME", than just a catchy phrase!
Can you guys hear me now?
Mic drop!