a few questions for you reloading guru’s.
i have a Henry Color Case Hardened 45-70 on order and hoping to get it this year.
the bullet weight that i am looking at is around the 350gr to 400gr.
so my questions are what powders should i look at using along with primers and should i gas check
Ar2207,ar2206h,trailboss
Yes you should gas check if you want to go over 1500fps as a rule of thumb
I use a short barrel rifle and I had success with 2207. 2206H will also work, just didn’t burn fully in my barrel. 2208 will also work, but also leaves a lot of unburnt powder. Trail Boss will definitely work, but will be very underpowered and anti climactic for a 45-70 
Large rifle primers… If you are not getting a complete burn, back off 1 grain and use magnum primers (then work back up), but 2207 seems to work flawlessly.
…what Bigpete said about GC. Unless you are using powder-coated (or jacketed) projectiles, then you won’t need to gas check.
You’ll find there are three sets of 45-70 load data, in your case use Lever Action data.
Any data for Marlin 1895’s is suitable for Henry 45-70 also. As mentioned there is three data types for 45-70
Antique for trapdoor springfields etc
Modern lever - Marlin , Winchester and Henry lever guns
Modern single shot- Single shot falling/rolling blocks like Ruger no. 1
Don’t mix them up.
I have the same rifle Henry CCH 45-70. They work well. I use 2207 for good results, they are stout loads.
I use Trailboss for my Big Game Rifle match loads in a Marlin 1895 behind a 405gr LRNFP projectile (both HRBC or Spartans are excellent), but I’ve had no joy using AR2207 - gun hates the loads and they kick quite a bit.
Right now when I go hunting I just buy a box of PPU factory ammo - recoil is manageable, gun loves it, brass is really good for reloading.
I’m thinking of casting my own bullets and using hi-tek powder coating or would I be better off buying jacketed
That entirely depends on you and how much you shoot VS how much you enjoy watching the paint dry (literally). Whether you are set up for casting, have molds, etc. If not, then not worth it. If yes, then depends on you preference alone. I do both, but considering how much I shoot it, I just buy jacketed pills.
It will mostly be for plinking. I have casting set up for my .357 revolver
Well, then it’s entirely up to you. It’s definitely cheaper to run, but a lot.
If it’s just for plinking I’d suggest buying pre-made cast & coated projectiles from someone like HRBC or Spartan. Works out at about 50c/projectile once you factor in postage, plus you don’t have to dick around with lead or casting or coating etc.
Should I also do a full case resize?
I do - don’t forget you’ll need to lube the cases because even though they look like a straight wall, there’s a slight taper there.
can you buy a set of dies or do you have to get them individually?
and where would be a good place to buy brass
You absolutely can get a full die set - I use a set of Hornady dies.
My brass is a combination of PPU brass I’ve kept from factory loads after I’ve fired them, and Starline brass I got from a gun shop having a sale.
Make sure you don’t use Hornady brass to reload with while you’re starting out - it’s a bit shorter than “standard” due to the fact it’s generally loaded with their rubber-tipped projectile.
Do I need to worry about trimming the cases
Generally speaking, in rimmed straight wall cases you don’t have to worry about trimming. 45-70 is not an exception. I’ve never trimmed any of my straight wall brass.
If a case is over length, it needs to be trimmed. Straight walled cases do lengthen. The rate at which they do depends on how hot your loads are and how many times the cases have been loaded.
The Hornady shortened cases are only found on factory “Levelution “ or however the fk you spell it, with the 325 Ftx projies. Yes the polymer tip makes the OAL a bit longer.
Some guns will cycle it at full length, some won’t. It’s only required for the FTX ammo though.
Perhaps a correct answer is, measure the case and make sure it’s within the specification.
Is there anything else I should look into or have??