Accurate 2015 Lot to Lot??

[deertroy1]

I recently purchased a pound of A2015 as the pound I had was just about gone. I'm familiar with this powder as I use it a lot in 45/70. I've noticed lot to lot variations in the past but nothing like this.
My go to load was 55gr with a Hornady 300gr HP. To see how my new lot compared to the old lot I loaded three rounds with each lot keeping all the other components the same.
Old lot = 1868 fps
New lot = 1601 fps

I've experienced this before but never to this extent.
I'm not sure I could fit enough of the new lot in the case to equal old lot velocities or even if I'd want to try!

Thoughts.

 

[Jager]

Yes, that's quite surprising.

Keith Anderson, the chief ballistician at Western Powders thirteen years ago once mentioned that their powders were allowed to deviate no more than +3% to -5% (measured by chamber pressure), lot-to-lot.

You're looking at just under -15% from your old lot. Which, if we assume your old lot was the hottest it was ever allowed to be, would still have your new lot 7% cooler than their spec should allow.

It's even more surprising because Anderson further alluded that they were holding their then-new LT-30 and LT-32 powders to half the variation allowed in their other powders. And LT-30 and LT-32 were derived from A2015, so it's reasonable to think that powder might also be held to the tighter standard.

I'd repeat your test. Maybe use five rounds each this time. And make doubly sure everything else is exactly the same - especially that the test rounds are all from the same lot of brass.

And assuming you get the same results, I'd inquire of Hodgdon.

 

[deertroy1]

I already sent an email to Hodgdon. Everything was the same. Bullets, primers all from the same box loaded in the same brass at the same time. Garmin chronograph that I had previously verified with an Oehler 35P.
Slow load also hit about 2" lower on target.
I measured the fired cases at the expansion ring. Fast lot measured 0.5048" while slow lot measured 0.5038"

 

[358WCF]

How old is the old lot? I have some 2015BR from '91 made in China that gives me c.100fps more @70* than a '22 lot of plain old 2015 made in Canada. Hornady 200SpPt, WLR, & Lapua 308 necked up to 358 Winchester. Same box of bullets, primers, & brass.

Someone's bound to come along & insist it's due to moisture content. Maybe? Maybe not.

 

[deertroy1]

I'm not sure how old the old lot is. It's in a green jug and the new lot is in a red jug. They are both made in Canada, as am I.

 

[SSL]

Pretty much why I buy 8 pounds of any Accurate powder at a time. It always seems to shoot faster in my rifles than the charts would lead you to believe. AA2015 always hit my targeted speed at least 1 grain under chart values. AA2200 I use a lot and it is pretty close to chart. The real surprise is my current jug of AA2700. In my .243 with 75-grain VMax bullets, it easily hits 3,500 fps in my rifle at 44.0 grains compared to the charts saying 46.5 grains to reach that velocity! Careful testing on up the scale yielded 3,650 fps at 46...where I chose to stop and go back to that 44.0 load.
Proves you don't take anything for granted- test it yourself!

 

[deertroy1]

Got a reply from Hodgdon. They said it's normal for powder ten years old or older to speed up as it dries out.
I'm not sure if my older lot is more than ten years old but I do keep notes on all of my loads. The speeds haven't changed much from when I first opened the old lot to now.
I upped my charge to 58gr of the new lot but still I'm about 100fps less than my 55gr load of the old lot!