I have used these to hold extra powder charges. In my state we can't use pellets. These speedloaders are great for holding extra pre-measured charges for faster followup, or quicker shooting at the range. I have not have them open up. In fact, they are kind of hard to open. They have always served me well in the field. I keep charges of 100 gr. of loose powder and this fills about 2/3 of the loader.
Fast to reload for you next shot. Tried others but the load thru is the best ever, once on the muzzle everything goes down the barrel. Needed larger powder room so had to go to the magnum speed loader, works great like the standard size but more room for magnum loads.
The caps plastic strap that connects the cap to the cylinder has broken off on both ends after 1 hunting season. The powder measure on the side is also not accurate, so you can't use this to measure your load, you'll wind up with a charge which is much too large.