In addition to being a powerful load due to being a very small granulation, Swiss powder is rated at about 10% to 15% hotter than GOEX, so your load is on the hot side. Try FFFg and see how much velocity you lose. I suspect it won't be much slower with the same volume of powder!

Generally they say to use 4F ONLY as priming powder for Flintlocks...

Although I've read of accounts of it being used for small pocket pistols such as .31 Cal. Colts and .26 Cal. Colt-Roots etc.

Don't think you want to be using it with ANY .44 cal. pistols.