Question re 45-70 Reloading

[Michael Olszta]

RCBS 3 Die Set With Rockchucker Press Being Used.
I've loaded many other 2 die bottle neck cartridges in the past but never the 45-70.
Today I resized, decapped, and expanded once fired 45-70 factory ammo cartridges. This all went well. However....
I have 2 bullet sizes to reload: 420 grain and 550 grain craters.
The 420 grain bullets fit perfectly using my hand. The 550 grain craters also fit nicely by hand but only the same depth as the 420 grainers leaving them way too long.
Question: When I use the seater die, will the 550 grain bullet seat so that the COL will be the same as the 420 grain OR do I need to expand further so the 550 will hand fit just like the 420 grain bullet does?
I appreciate any instruction I could receive on this.

 

[JD338]

The longer bullet should just slide into the case.

JD338

 

[RL338]

The 420 grain bullets fit perfectly using my hand. The 550 grain craters also fit nicely by hand but only the same depth as the 420 grainers leaving them way too long.

How far are running the expander die down? I only expand the case mouth to form a bell to start the bullet. From there let the seating die do the work.
Yes you will have to adjust the seating die for different length bullets to arrive at the same COAL.