Could the malfunctions be a result of 'limp - wristing?'
Very seriously doubt they are limp wristing that often in a competition.
I have to lean more towards the mods and hand loading combos.
If you are talking speed shooting then recoil is the enemy and if they are hand loading light rounds the 17 and 19 won't like them.
Light loads can have the same effect of limp wristing in those models.
What i am unsure of is if they are using light hand loads.....Anyone familiar with the kind of hand loads they use as far as light or heavy?
Also what kind of competition shooting were they doing during the malfunctions? Speed between rounds where recoil comes into play?
Something has to be different and what ever that difference is, has to be leading to the malfunctions, whereas a 20 year old Glock with 100,000 rounds by an everyday owner has little to no malfuntions.