A paper patched primer for people???

[Fox Creek Kid]

But since modern casings won't reach that I am not overly concerned with volume but more the bullet weight.

Yes they can.......................with BP slowly drop tubed AND with PP bullets barely seated into the case. I know as I've done it. 

[Black River Smith]

Yes, you are correct with bullet depth.  I did not factor that in.  You are correct.