The problem with small charges of fast powder in big cases is it is very easy to throw a double charge, especially when you are in the middle of a reloading task and go to fill up the coffee cup!
There is no way I would use that 34 grain load in my 338 Win Mag.
You also need to think about S.E.E with that light load. Under the right conditions it could occur.
I've fired a few thousand reduced loads using fast powders in cases from the smallest 17 M4 to 45-70 using jacketed and cast. Not one double charge, and not one hint off SEE. It takes a bit of know-how, but it is inherently safe if your loading technique is.
