Link to the main picture : here
Thank you to 9gag for this short and interesting video : link
And in the comments, as you might have see, there is this picture :
The person who sent the picture said : “Those are called patrons. Preprepared most of bullet, you just stick ignition part onto gun. It takes me around 40 sec to recharge 6 bullets prepared like that”.
I looked for them. But I didn’t find them. On the other hand, I saw that there were some paper cases (like in the main picture). And for example, this company sells some : link
Aquila