SKS Fail To Feed

[u/thecoop1999]

I've been having this issue with my SKS where the 5th round feeds vertically and the bolt carrier slams into the side of it. This happens between 3 and 5 times per 100 rounds

I've seen some solutions online but don't fully understand the terminology used to fix it

Has anybody else had this issue and know how to solve it?

[u/sounoriginal13]

Is it numbers matching magazine and receiver etc