I think you will get a lot of blowby into the action if you use a 170 gr bullet. If you read about 45LC users shooting BP in their rifles you will see that the least blowby occurs with the biggest bullet and the highest charge of powder (meaning no filler). And even then they will get some fouling into the action unless they try such tricks as annealing the brass. In my 44 spcl 1866 I have mostly used a 240gr bullet with BP, plus a full charge of FFFg, and the action still gets pretty dirty. Now, having said that, I never had it seize up on me during a stage due to fouling, though I did have to spritz the carrier area with a mist of water or moose-milk (water/ballistol) once or twice during a match if the humidity was low.
As for cleaning the rifle, other than the bore, I just cleaned the carrier area with a bunch of Q-tips dipped in moosemilk, and then sprayed some oil (ballistol or Tri-Flow) and worked the action before putting it away. This oil gets into the links area and neutralizes any fouling in there. I only took the side plates off of the '66 to clean the inside about once every couple or three years. Yeah, it was pretty gunky inside but no rust.
Of course, BP in any caliber runs fine in most pistols.