I've been having problems with Winchester SP primers loading 38 super. In a run of 500 rounds, I will get 3 or 4 incidents where the case is fed 2 primers. I have to add significant pressure on the handle to cycle my 1050 and the case that was over the double primer is jammed cockeyed in the shell plate when it arrives at the powder station. I have to remove that case because the primer looks as though it has been fired. The case will not fire after this. The primer that was forced into the seated primer falls out on the loading bench flattened. No problem with Federal but I have about 15,000 Winchesters that I recently purchased.