Awhile ago when I started working up a ground squirrel load for my new Savage M12. I called Hodgdon because I could't find data for H380 in a .223.(had a nearly full 8 pounder) "that's because it isn't suitable, don't use it." I was told. Went on to other powders and found the gun likes 53 grain MKs. Today I tried the MK with 27 grains of H380. Groups in the threes. Guess the experts can be wrong like the rest of us.

Quickload guesstimates

3165 fps and 47K PSI pressure for that load.

YMMV

Hodgdon has it listed in their number 26 manual... with load data from 40 grainers right up to 70 grain Speers...

MV don't not have that much variation... which I think makes it quite useful...right around 2900 fps with the heaviest bullets to 3100 fps with the lightest bullets.... that way you don't see much of a change of Point of Impact at 100 yds, regardless of bullet weight...

I have never used it with Mag primers... regular small rifle primers work just fine...

and as far as accuracy, it has always been a tight shooting powder... even in several rifles with advanced throat erosion...

face it, call tech support, and they tell you exactly what they want you to think...meaning whatever the current company line is, according current gospel in the legal dept...

even if it conflicts with what was company guidelines in previous years.... and the way they get around that contradiction is to to the public that the older data is 'obsolete'... and the gullible just accept that and move on...

H 380 works just fine in the 223, and actually is pretty user friendly in that small neck... same as it is in a 22/250...