Noe is cool because they sell the mold, the top punch, and the adapter to use the top punch in a Lee seating die along with the two step expander to round out the system.... I don't have their top punches because I use rnfp molds and just use a swc seating plug. They have a great system worked out
The two step expanders fit in the Lee universal expander body. I have and use those. The collar and top punch I don't use and think they may also fit in the expander body, but I haven't done it myself. I have piles of loaded 45-70 from dad so when all the stuff gets here next month I'll have to go through it all. I'm sure the mold is a 385 grain, so I'm in a lightweight class in comparison.
Yes, you are closer to the range of bullet weight that I would LIKE to be in. But, I have been told that trying to shoot 600 yards with a bullet lighter than about 500g won't work very well. It gets pretty interesting when you throw in the transonic region issues. With normal modern rifle loads, you are well above the transonic region unless you go out quite a ways PAST 600 yards. I have fired my my 6.5 Creedmore PGW scoped rifle only as far as 300 yards so far, but my 120g handloads for it are producing reliable 5-shot groups barely larger than 1/4 MOA. The velocity stays WELL above the transonic range.
But the buffalo rifle is very different. There, you have a choice on how to handle the transonic issues. You can in theory TRY to stay above the transonic range, but the BC realities of 45-70 bullets would then require muzzle velocities in the rnage of 2000 fps. A 500g bullet at 2000 fps is going to generate very strong recoil (PF = 1000!), which is hard on the shooter, and probably not great for the mechanical pieces on the historically semi-authentic scope with its primitive EXTERNAL mounts and adjustments and its SLIDING mode of operation. After each shot, my scope needs to be slid back "into battery". With muzzle velocities in the 1060 to 1400 fps, it "moves" on recoil over an inch (actually, it is the rifle that moves on recoil, not the scope, but nevertheless there is that high speed relative movement on every shot).
Or, you can try to keep the bullet velocity BELOW the transonic zone. But, that is in reality, really impossible, because transonic effects apparently appear over a range of speeds several hundred fps wide, starting at well under 1000 fps and running up past 1300 fps! So, a slow bullet cannot avoid them. Also, the trajectories associated with 500g bullets at slow speeds get ridiculous. My historically semi-authentic scope has over 200 MOA of externally adjustable height. And then of course, the slow speed coupled with the lousy ballistic coefficient of a 45-70 historically semi-authentic bullet, results in really big windage effects at even modest wind speeds.
So, considering all the options and impediments, you realize you need a bullet that can successfully mitigate transonic effects. But advertised bullet specs don't include any measure of transonic effects mitigation.
So you try to read a lot of forum postings to find out what others have managed to make work.
This makes for a slow and sometimes frustrating load development program, but great satisfaction when you finally achieve reasonable success.
Jim G