I worked on a 742 that the owner had problems with feeding. When he brought it to me he actually had a stuck round in the chamber. After clearing the round I found it had been fired. A thorough cleaning of the chamber showed it was very dirty. Like any auto loader proper maintenance is important. Unlike a bolt action there are many moving parts that need to be clear of even small amounts of dirt. The main culprit is over oiling. Oil is a magnet for carbon buildup and when heated it will turn rock hard. I used Hornady One Shot Case Lube to lube everything after the cleaning. It is used for lubing Brass Cases during re sizing in forming dies while re loading. It lubes but leaves no residue. He never had a problem again. I use it on all my auto guns.