I beg to disagree. Max loads with heavier than originally loaded bullets is not the way to learn to shoot a 100 year old rifle. The original bullets were 260 to 330 grains in the older loadings. Only the later nitro for black loads used a 365 grain bullet and you want to start with 400 +/-?
First order of business is to do some research. Graeme Wright and Ross Seyfried are two knowledgable authors on the subject. Contrary to some advise already given a 10 or 20 grain difference in bullet weight can make or break your loading efforts, heck even the shape of the bullet can effect regulation. The thought that a 40 grain heavy bullet will make no difference reflects a lack of experience and research. Best thing you can do with the heavier bullets is to trade them for some lighter ones, the RCBS 300Gr flat nose gas check is a good one for this caliber, I use it in mine.