Your last question was for my thoughts THEORY, concern.
I will never give my theories to anyone. When I get one I prove or disprove it by experimentaion. When I learn the facts I tell anyone interested, and never disclose my theories.
There is no concern about gas checks being pushed off inside the case, due to the heavy sizing being done by the Lee factory crimp PISTOL dies, but bullets are often loosened, because the sized cases spring back from sizing more than the bullets, which ruins performance due to lost case neck grip. In my experiance with one of those dies, only part of the bullets were loosened out of a lot of sized ammo. For this reason I definately reccomend against ever using the Lee Factory crimp Pistol dies. If bullets are too large to chamber, fix the bullets before loading. And pull the bullets on any ammo which doesn't chamber easily.
So, if loaded ammoy chambers easily with the .360 diameter, shoot it. Oversize cast bullets DO NOT increase pressure compared to bore size. If it doesn't follow the above directions.
The Rifle dies are another matter entirely, as they crimp only, and can be adjusted to crimp to any degree desired, with or without the bullets having a cannulure. They are useful in many situations, and especially for most levergun ammo when bullet seating depth needs to be adjustable.
