Alliant 2400 lot variation ?

[NeroM]

Finally, after almost a year of searching - I was able to obtain a canister of Alliant 2400. Presume this is a newly manufactured lot as the LGS just received it in stock. Have been loading 357 Mag with "2400" for over 40 years, i know there are now some newer more energetic powders available - but this has worked well for me.
Loaded up a few test rounds with the new powder..... it is a little less dense than my previous "lot" which was a mix of the dregs of several older lots. A Little Dandy rotor #13 delivered 10.4 gr for the old lot and 10.2 gr with the new lot. Old lot yielded 1080 fps with a 187 gr WFN-PB bullet and 1050 fps with the new lot number ending in ....052522.
I know there are usually some lot to lot variations, has anyone used this lot, obtaining less velocity than in a previous lot(s)? Or perhaps my old lot mix was a little "hotter", due to slightly higher
density ? Thanks in advance for your feedback.

 

[ballman6711]

I don't use 2400, so my thoughts are worth what you're paying for them.

30 fps could be due to a 0.2 gr difference in your charge weight. If your load is accurate with the new 10.2 gr charge, then I say run with it. Paper, cans, or deer won't know the difference of 30 fps.

Finally, after almost a year of searching - I was able to obtain a canister of Alliant 2400

My LGS had some powder, including 2400, just two days ago. 8 lb jug IIRC. Flat Top Arms in Beckley, WV, if anyone is interested. Since I wasn't looking for powder I never asked for prices.

chris

 

[Slamfire]

How many rounds do you use to calculate average, mean, standard deviation and extreme spread? My chrony chrono only goes to 32 round strings, but I would prefer 50 round averages. Smaller strings are very suspect.

Humans model things, make assumptions that are not backed up by data. One of which is that better throwing powders will give tighter velocity spreads. I have not found that to be the case. In the 45 ACP, Bullseye pistols loads have tighter extreme spreads than AA#5, even though AA#5 is a fine grained ball powder and thrown charge weights are extreme consistent.

I have never seen a study showing the sensitivity of velocity compared to thrown versus weighed weights. And also, this is a handgun you are using this ammunition. I am going to state, your aiming error is orders of magnitude greater than your ammunition error.

 

[THEWELSHM]

It was good enough for Elmer Keith, I use it and AA#9 for all my Magnum loads, almost identical..

Thewelshm

 

[Swampman]

...A Little Dandy rotor #13 delivered 10.4 gr for the old lot and 10.2 gr with the new lot...

Just so we're clear, were you shooting equal weights of both powder lots, or equal volumes as thrown by your powder measure?

 

[.38 Special]

I find that I often have to reset a measure day-to-day or week-to-week. I'll load a hundred on Tuesday, empty the measure, refill it on Sunday and discover that it's now throwing a tenth heavier or lighter. Humidity? Barometric pressure? Elves? I have no idea, but there you go.

 

[243winxb]

This pressure test with 2 different lots of 2400 and 6 different primers may be of interest. https://castboolits.gunloads.com/sh...00-in-the-357-Magnum-with-6-different-primers

I use the WSPM. Might be why my maximum is 13.5 grs with a 164 gr lswc? (357 magnum)

Its interesting that the WSPM over pressure loading, produced the best accuracy at 50 yards.

New lots of 3 other powders i checked, buy volume, were heavier then the older lots.
Older lots of powder are said to outgas, making them lighter over time.

A study of 6 different lots of H4831 powder showed a 10% difference for slowest lot to fastest. If the load was worked up to maximum, using the slowest lot, changing lot to the fastest, resulted in over pressure loads.

Edit- Added link ,https://apps.dtic.mil/sti/citations/ADA572333

 

[Bfh_auto]

This pressure test with 2 different lots of 2400 and 6 different primers may be of interest. https://castboolits.gunloads.com/sh...00-in-the-357-Magnum-with-6-different-primers

I use the WSPM. Might be why my maximum is 13.5 grs with a 164 gr lswc? (357 magnum)

Its interesting that the WSPM over pressure loading, produced the best accuracy at 50 yards.

New lots of 3 other powders i checked, buy volume, were heavier then the older lots.
Older lots of powder are said to outgas, making them lighter over time.

A study of 6 different lots of H4831 powder showed a 10% difference for slowest lot to fastest. If the load was worked up to maximum, using the slowest lot, changing lot to the fastest, resulted in over pressure loads.

That's a very interesting read.

 

[rfwobbly]

Lot-to-lot power variations have decreased over the years the since the introduction of computer controlled processing in manufacturing. Use of extremely accurate chamber pressure test and measuring equipment since the late 1990's has also contributed. In the 1970's lot-to-lot variation was a concern, in 2022 it's almost an after thought. This is unless you're shooting in national or world competition.

► However, if you have ANY concerns, then you should work up your loads again. Beginning, of course, at the Starting Load. The basic rules of reloading safety dictate this.
.

 

[Rule3]

There is just to little information (data) to conclude anything about this.??
Powder density can change for a number of reason which is why we measure by weight. My bottle of 2400 will be different from yours even if it is the same lot number.

 

[GooseGestapo]

Typical lot to lot variation.
I have an ancient lot# of Green Dot I was gifted.
Velocity by weight is spot on, but it’s far lighter, by volume.
It takes 2 cavities larger to match weights with data.
It’s just “fluffier”!

 

[FROGO207]

Typical lot to lot variation.
I have an ancient lot# of Green Dot I was gifted.
Velocity by weight is spot on, but it’s far lighter, by volume.
It takes 2 cavities larger to match weights with data.
It’s just “fluffier”!

This is why all reloading manuals use weight to set propellant amounts. The volume can vary by the lot. As mentioned always do at least an abbreviated load workup when changing things. It has saved me grief many times. I have noticed different velocities when loading the same volume from the same keg years apart. Not enough to change anything but it was different. Older was a bit faster on average.

 

[Rule3]

There really is no variation if the OP used two different weights??10.4 vs 10.2
The powder measure varied!