QUESTION #1 Is it OK to seat this bullet down deep enough past the crimp groove with 50.5g of 4198?
I would worry, as your DECREASING powder capacity. Doing that will RAISE pressures.
QUESTION #2 Should I be crimping at all?
I do and prefer it.
QUESTION #3 What are your pet loads specifics. Bullet, powder, crimp or not, COL for a non- throated Handi?
I haven't herd of needing to "throat" and 45-70 H&R... A 38-55 YES.
QUESTION #4 What are the safe load levels for the Handi? trapdoor, modern or Ruger no1?
Every gun is different, start lo and work up. But YES generally speaking the H&R is considered a STRONG action. At least capabule of "Marlin" level loadings. MOST give up far before reaching TOP loadings.
Does anyone else get confused by this cartridge?
Badge54
This is excellent advice and I agree:
1. COL of 2.55 with a max case length of 2.105"
2. Not really necessary but I like to crimp slightly
3. 405 grain LFNGC over 30.3 grains of IMR4198 and also I like RL7.
4. Modern loads so you can go mild or load her up if you can take it.
Just load it to the COL of 2.55 and you'll be fine!
I have 5, 45-70s and none have a problem with a correct length casing seated to the crimp groove. My Marlins don't like the 400G speers longer crimp groove, but my H&R's and Browning DO!
Here is a LONG seated 405:
Here is a SHORT seated 405:
I don't like to post data, but with your having a manual its not necessary, you have good data! 3031 is a very good powder for the 45-70! I prefer 4198, but 3031 is a good choice too. I use a CCI LR primer. Cases matter little, and Starline makes some of the best. Your choice in bullets will also serve you well. I prefer a 400 Speer, but that's just me, I like heavy bullets.
As for a powder charge, as I said I won't list any. But I will tell you 1500 or so FPS works just fine and even factory equivalent loadings of 1250fps for a 405g will kill just as well and any stomping load you could conjure up...
Be sure your brass is trimmed to correct length, and seat to the crimp groove and you should be fine. IF you NOT, double check your numbers and if correct, send it back to the factory, something is wrong.
Lastly, there is no reason to "kill" your shoulder when using the grand old 45-70. Factory level loadings work JUST fine... Want a litmus test? Do you think the 454 Casull is enough for deer form a hand gun? Of coarse it is!! Well TRAP DOOR level loadings meet or exceed the 454 from a pistol... Does that bring it into perspective for you?
CW