M700/M24 users

[wilko129]

Just finished upgrading my KJW M700 but I am having a problem with the magazine/loading system of the rifle. Whenever I use the rifle, BBs still held in the magazine seem to get black marks on them from the air nozzle moving past them to pick up the BB above them. Here's a picture or two of what I mean. I cannot seem to work out how the air nozzle keeps getting dirty to do this as I have tried thoroughly cleaning it a number of times and the problem persists almost immediately.

Has anyone had the same issue and if so how did you go about fixing/avoiding the problem as having dirty BBs go down my TB seems a bit counterproductive?