There is several ways to fireform brass. What works best is up to you.

When I fireform PPC cases I take a small piece of cloth saturated in oil, and give each shell a lite coating, this helps then to fit better, and keeps them from sticking. I jamb the bullets hard into the rifling, that way the case head is against the bolt face. You don't need to load to the max, all it does is beat up the brass, a moderate load is all that is needed.

When I fireform necked down brass, 6x47L and 22BR ETC I use small load of pistol powder and Cream of wheat. (No bullet) This works well, as it blows the donut out. If you don't know what your doing please don't try this. I don't recamend it it is just an example of how I do things.

Some benchrest shooters fill the case full of pistol power (No bullet) and fire it. I highly don't recemend doing this, and this is only an example on how some shooters do this . To add some shooters just load the rounds up and shoot them. Like a 220 Russian (22 bullet) in a 6PPC. On AI chambers (Like a 22/250 AI)some shooters just buy (22/250 rem) winchester whitebox in the parent caliber, and shoot it.

You may be surprised, I have found that a lot of times that the guns shoots just as good if not better when fireforming cases as shooting formed cases.

A few good articles to read.
http://www.6mmbr.com/6improvedform.html
http://www.6mmbr.com/260AIforming.html
http://www.6mmbr.com/6PPC.html
http://www.6mmbr.com/CroneBRX.html