Way back in the day when people were blowing up 38's with the dreaded 3 or 3.5 gr of Bullseye, Hercules/now Alliant did some in depth testing of this phenomenon and absolutely could not duplicate any load that caused a KB. Their conclusion was that since people were using such small charges, that they had to be either inadvertantly double or triple charging cases and that was the reason for the KB's.
They wrote an article about it in the NRA Handloading book (Published January 1981) The author is Wm. C. Davis JR., pg 113. Titiled "Reduced Loads"
If you have or can dig up a used copy of that book, it is an invaluable resource with many good articles. I lucked out and found a copy. If you can not locate a copy, PM me and I'd be glad to zerox you a copy of the article and send it out to you.
Awhile back I had the same idea you do about loading reduced loads (for my nephews & such) so they could shoot my small sized but big booming CA Bulldog in 44 special. Against most (but not all!) peoples advice, I loaded some up with 1.5 gr of Bullseye and a 180 gr WC and even went as far to consciously tip the gun down to ensure the powder was against the bullet
before firing. Well guess what? No KB's and I actually got very consistent results with about 350 fps and an AVG DEV of 6 fps. No squibs (short barrel!) and less powerful than a 22 LR. (50 ft lbs).
I do not know conscientious of a loader you are so can not recommend that you try this. But if you do bear in mind that I hand weighed each charge, and checked for squibs after each shot. My barrel was 2.5". The longer your barrel, the greater the chance for a squib. So it can be done but you must excercise as much care in loading as you do for max loads.
WHatcha gonna use em for?