When I’m trying to stuff summer sausage of snack sticks the seal on my stuffer pops out the top. I am not trying to go to fast or holding the casings to tight. Anyone else have that problem ? How do I stop that from happening ?

I have not used any kind of oil or lube on the gasket. Some times it works good others not. And the spring on the air vent seems to be fine. Could the meat be to sticky ?