my 2 cents - most often the jags break when they become loose. It you push your rod down the the rifling in the barrel tends to turn the jag out, when it becomes loose it has a real tendancy to break at the stud. If it stays tight amd compressed up against the rod you are less likely to get the breakage... If you use a range rod that allows the rod to turn as it goes down you probably will not experiance the breakage - myself I try to tighten the rod at the bottom of each stroke... If you are using your gun rod try to allow it to twist in your hand.

Just a thought