Bullet selection is important. Some of the heavier bullets work better for some guns. The .405's are available comercially, but if you shoot it a lot, and work up loads, you may as well start loading for it. A friend has a Quigley Sharps, and he reduced his groups more than 1/2 by seating the bullets just off the lands. The old soft vs hard will be delima for a while too. I always use a wad with either powder choice. Keeps the leading down and also leaves the bore lastly.
Chey Cast in Cheyenne, Wyoming, has a very good 494 gr Spitzer that I have used for years. Lots of grease groves and 1-20 mix. Great bullet!
With your new rifle it will be a pleasant experiance for years. Strive for 5 inch groups at 200yds. Then it will hold 20 at 500yds.
Pack
Sheriff Pack Wolf, SASS 31917