Mr.Coffee

I guess i should've been more specific i am wondering WHY this is happening i already know how to fix it but why is it locking like this, is it because of the dummy rounds or an actual issue with my rifle?

So I have an AR10 80% that I built I have finally gotten everything together and working. I wanted to make sure that it would cycle rounds so I loaded a magazine with some snap caps (dummy rounds) pull the charging handle back and it loads the first round perfectly then i pull the charging handle back and let it go as fast as i can, the first round ejects and second round loads everything worked great. Then i try to pull the charging handle back one more time to clear the round and it wont budge. I did some research and found how to get the bolt unstuck by pulling the charging handle and slamming the stock against the ground. I'm not sure whats happening it looks like the bolt isn't returning to the proper position when the second round is pushed in. Is this something that will be rectified when i shoot live rounds? or is this a malfunction that I need to deal with beforehand?