Originally Posted by .220swift

As Grandpa stated; fired out of battery.
Before thinking firearm malfunction inspect for grundge in chamber,
ammo issues.
I actually had same issue with a 15-22 while grand daughter shooting.
First I cussed S&W as brand new firearm.Nobody hurt as all safety equipment was worn. I totally agree with the shock of it all.
The OOB round was WAYYY louder.I thought son was screwing around and him the inverse!!!After sitting on step{rancher} mussed about we decided to do some CSI. Checked chamber and bore all was fine.
Filled 10 round mag hung gun around very large rock and fired 5 slow 5 fast no problem.Next culprit ; ammo; that evening dug out reloading measuring tools.Had qualitve and Quanitive analysis in college.Turns out ammo had very serious quality issues.Issues of canted bullets out of round case heads etc. When anybody but me are shooting only ammo is CCI;brand used was from way south. In revolver or single shot will work fine in semi auto best find different brand. Only a couple per 100 but that's enough for your mentioned incident.Just food for thought.Rimfire ammo should be checked before shooting I use a go no go die on all centerfire and once in a blue moon I will have a reload out of spec it happens.Researching one for .22 now. Food for thought.