Marui MP5 firing inconsistently
 

I've got a Tokyo Marui MP5 that just recently started firing incosistently. It'll shoot maybe 10-15 rounds properly and then the next few will just lob out of the barrel maybe 5 yards or not fire at all. Any help would be great.

could be a long shot but look inside the mag well. look for a crack in the mechbox. I had the same problem with my m4 one day. turns out I had a massive air leak. lol