I bought mine from Wideners ($85+HZ+SH). I know they tested 846, and they have a note saying how they tested it. I wish they did that for 844, but they just say "If you reload 223 you know this powder."
"WC844 Original application is U.S. 5.56mm NATO Ball M193 (55gr) & M855 (62gr),
plus Tracer M196 & M856. Typical starting load for 55gr bullet is 26gr,
and 62gr bullet is 25gr. A ball powder which can be loaded with Hodgdon H335 data.
Also works great in 7.62mm NATO (.308 Win.).
This is pulldown powder.
$100/8# jug. $376 for 4 jugs. $528 for 6 jugs ($88ea)"
I trust their statement as it is consistent with TM-43-0001-27.
I am not disputing your post. My point though, despite lot variances, "was 844 actually a different powder than H335?"
I suspect 844, on average across all lots, actually burns slower. IF
true (and that is a big IF
) then 844 may be usable beyond H335 published loads, if it is actually a slower powder (and for me more useful than H335 is in loading 308).
I think sellers of surplus powders are ALWAYS going to reference a faster commercial powder, and Never reference an actually slower powder. To do so would risk pressure increases beyond SAAMI ranges. I think referencing an actual matching speed commercial powder is unlikely because that would not be safe with lot variances.
On the other hand, H335 may actually be a commercial version of 844 formula at the time Hodgdon introduced it, and both have been kept stable since. I don't know.
I was hoping Quickload would be able to shed light on this. However, I was disappointed to find their website does not list 844 as one of the powders it has data for (must only have H335).
I am just challenging the assumption they are really equivalent, or, do we reference H335 as convenient faster data to fill an inconvenient data void for an actual burn rate that is slower?