As you noted a very easy to do wildcat. No need to anneal the brass. Just very, very, very lightly lube the brass and form with your full length sizing die adjusted so the frame will just snap closed easily with a case chambered. I preferred Imperial Sizing Die Wax for all the wildcats I did. Make sure you get all of it cleaned off the brass afterwards and before loading. For the 444 based JDJ's I also ran even new brass through a 444 die first for good measure. I probably made thousands of 309, 338#2, 358, 375 and a few 416JDJ's over the years with no lost cases.