Ok so this is my first batch of .45-70 loads.
Lee 3 Die Set and Factory Crimp Die

Cast bullet 405gr .458 diameter (Cast Performance)

Using Remington nickel plated new brass

After lubing and full length sizing all the brass then priming and charging of course no matter how I seem to set the expander die up and no matter how wide I flare the case mouths the bullet barely fits it's base in the mouth.

Once I seat it you can see a bulge for the entire length of the bullet. At the base of the bullet it neatly tapers back to the size it was before seating.

Is this because this is never fired brass?

Will this go away after firing it one time? But will I then full length size it and see this all over again?

Do I need to size it after it has been formed to my chamber after firing it once?

By the way, the loaded rounds drop right into my chamber no sticking no forcing just drop right in as normal.

Why the bulge???

Not to worry!!

This is a normal occurrance. My 45-70 cases are only partially resized after firing (just enough to put some tension back on to bullet seating area) and the Hornady jacketed bullets will also exhibit a slight bulge for the length of the seated bullet. We're dealing with a pretty thin walled case here, and the bullet is gonna show.

Like you say, if the cartridge slips easily into and out of the chamber, you're OK.

Might consider adding a Lyman "M" die to your set at some point in time. It helps with the bullet seating.

kdub, thanks again!

Well it looks like I should have my all my test loads finished tonight then. I started at 52grs 3 rounds, then 54grs 3 rnds, 56 grs 3 rnds, 58grs 3 rnds to check for pressure signs. I might even be able to borrow a chrono this weekend. I don't see any problems with them then with this question out of the way.

Tomorrow I'll load up maybe 10 more of my starting load so I can play around with it before I leave the range Saturday.

Thanks for all the help!

Oh what does the Lyman "M" die do? I have not heard of that one. Does it support the case more maybe?

Go to the home page here at BTB, click on "Tech Notes" and read the article by MikeG on "M proving on the Lyman "M" die" dated 02-02. It will explain about the die.