For what it is worth, I love Vihtavuori premium handgun powders! They seem to meter properly and 3N37 seems to be almost universal for the calibers that I shoot. I shoot 8.1 gr Viht. 3N37 with X-TREME 185 gr. HPCB bullets. They are accurate and cost-effective. (BTW, I use Starline brass)

I have also had good success with Acc. #7.

Also, sometimes people complain about the additional cost of Viht. powders, but with most everything going up, it seems Viht. has increased in value!

I would feel uncomfortable using 40 S&W in the 10mm. It would be fine with a conversion barrel, but I would NEVER risk my life or pistol just to try it out. Like someone said, in a SHTF time I might give it a try, but that is all.