So background here, I had this issue a few weeks ago loading 45ACP on my 550, and now last night on my 750.
I am having primer feed issues only with Winchester primers. Both LPP and now SRP. Loading the primers the old school way with the primer pickup tubes, occasionally a primer will get stuck in the pickup tube while loading. It's definitely a primer itself gets stuck somewhere in the tube and I have to push it to get it to go through the tube into the primer tube in the Dillon. The same primers also cause issues periodically on the press when they refuse to drop through the plastic tip into the primer loading cup. It creates a big mess when the powder drops into a case without a primer when this happens.
This is only happening with Winchester primers (LPP on my 550, and now SRP on my 750). Same issue both times. Never any issues in the same pickup tubes with CCI or Federal primers. The issue starts when they get hung up in the pickup tubes initially.
Is this a specific issue with Winchester primers? I generally avoid them but have a couple K due to the shortages the last few years.
Also - How do you clean a Dillon primer pickup tube? A .22 jag or patch end is too big for the tube. I can use it on the machine primer tube though. I don't see anything in the primer pickup tube but want to run something through there to clean it in case there's something I can't see.