I trust my reloading abilities and my common sense. Powder is still available and experimenting with an unknown, potentially dangerous powder just isn't something do, as an adult. 40 years ago I might have tried it (here, hold my beer and watch this) but not today. Besides, I don't have any high tech equipment to measure pressures, etc....
Hmm. Let's see; 4 lbs powder, $100.00? Cost of a new 629? $950.00...