That is very true, Back to your FN19, If i remember correctly they work by bye way of an indexing probe rotating the magazine prior to the pellet probe inserting the pellet, Does the bolt cycle ok with no magazine fitted? If yes, its possibly the cog on the back of the magazines that has worn as they are plastic and do wear over time, If this is the case then there are two options, Covert the gun by removing the need for the indexing magazine probe by means of a kit purchased from ebay or buy new standard magazines,