@Michael458 of the two machined bullets, do you find that the hp is any more effective than the big meplat? Obviously either is more than adequate for squirrel (I’m being facetious in case that isn’t obvious) and deer and such, I’m thinking bear.
Jim, the HP as you refer to is actually a modified CPS, or Cup Point Solid. Standard CPS does not expand, however John at North Fork designed these to actually expand, and they do an incredible job with expansion and extreme deep penetration. However, the problem is, North Fork is no longer in business after October this year.
The Solid is specifically designed for 45/70, and is very effective, and gives extreme deep and straight penetration. Of the two for bear, I would opt for the North Fork CPS, if I could get any. CEB also makes some dandy Lever Raptors, HP's, that would knock any bear in the dirt, and are available.
Those Bullets from North Fork and CEB are extremely high performance bullets designed to get the very most out of 45/70 that you can get. I have had guys use these even on Cape Buffalo with great success, and wish that I would have had them back in the day I shot Cape Buffalo with 45/70, but back in those days there just was not anything like that available.
You don't really need them for black bear however. If it were brown bear, yes, I would be opting for these, but for black bear, even the big ones, there are many good conventional bullets that would do fine.
Without doubt RL 7 is the way to go in 45/70. I have tried a lot of different powders, including IMR 3031, and while you can get good loads with any of them, RL 7 still comes out consistent and on top. Especially with bullets less than 400 grains. At 400 grs IMR 4198 comes out best with velocity and keeping pressures lower. 350 or less, RL 7. You do have to know your keg of RL 7 however, there are lots of inconsistency between Kegs or different containers, lot# does not much matter. But RL 7 is good enough that when I buy say 15-20 lbs of it, I mix it all together in a 5 gallon bucket, then put it back in containers labeling the date I mixed it, and then test it. This way I have however many pounds that are the same.
Extreme low velocity loads, IMR 4198 comes out on top with most anything. No hangfires. At least I never had any.