I have a special pattern for heavy 50 Alaskan bullets and would recommend that for the 500 gr. It is called the AK.
For 450 gr and lighter I recommend the LFN.
I'm not certain if the Lee Factory Crimp die is available for the 50 AK, but if not you can have your Rifle smith make up a crimp collet which will work in the body for the largest caliber Lee offers. I recommend using this crimp method, and ordering the bullet without crimp groove so you can play with OAL for best performance and be able to keep up with throat wear if it changes performance after extensive shooting. If you intend to use compressed loads, which is my preferred method of loading most lever gun cartridges, no crimp is needed, as the powder will prevent bullets from being jambed deeper into the case from what most people believe is recoil. The hard slam on bullets in the magazine is caused when the stack comes back after levering a new cartridge in, and after recoil pulls them forward against the spring. Perhaps this seems a bit like a tech snoot but I solve the problem of battered bullets in lever guns by carrying only one or two in the magazine. I find my extra ammo carries a lot lighter in my pocket than in the rifle magazine, and bullet impact is less effected as weight decreases only one or two cartridges. I've never used more than two shots on one animal in my 50 years of hunting, and only a couple of times at that, so I don't get uptight about having only one cartridge in the mazizine of any rifle. I do the same with my bolt guns, if I'm doing a lot of foot work, to but only tokeep weight down on them.