Just out of boredom I'm considering having another crack of shooting PP bullets in both my Stevens 44-5 which is in 40-60 Maynard, and my Meacham 40-65. In the past I tried PP in my 45-90 but with no good results, at least not as good as the greasers. Left over from these experiments I have a quantity of paper which I think is called "Onion Skin"  I obtained this from BACO about 5 years ago. 
What I want to know is what dia mould I need that BACO might have in stock. Both rifles have different barrels, ie, Krieger and GM if this makes a difference. To the best of my knowledge both are the same dimensions internally, 16-1, 400, 408.
Mike.

I have been playing with PP for just two years maybe and the one thing I know for sure is that you need to do a chamber cast for each rifle to see what the diameter is just in front of the case.  I try to use a dual diameter bullet that patches close to this diameter with the nose riding section being a snug but not tight fit as I am using the bullets to hunt with.  Paper only costs a few dollars so don't worry about using what you have although there is nothing wrong with the BACO paper.  I think my Baco paper adds 0.007 to my diameter if memory serves me correct.  By casting the chamber you can tell how long the base diameter section needs to be when seated 0.10 to 0.15 deep.  Hopefully your fired brass can be loaded without sizing if the chamber was cut snug enough.  I can also say that I have had much easier results with blackpowder versus smokeless.  Beltfed/Arnie is the go to guy on dual diameter PP bullets. Tom

Beltfed
I just tried the BACO web site and could not locate the 403380E mould, it also looks like every PP mould listed is also out of stock.
Mike.

Mick,
Baco does list the mold 
Item Number:  JIM403380E
You have to go thru the sequence:
Bullet molds
Baco molds
Baco PP molds
36-41 cal molds

They also list the JIM405390E, which is the same length as the 403380E, but a shorter base/major diameter band for chambers with less freebore.
Yes, you will see that Baco lists most molds as "out of stock"
They operate mostly on an order basis,
and then they will "Q" you up in line for when they have mold blocks available to cut the mold.
OH, and you can adjust the Diameters of the PP molds to suit 
your particular chamber.
As has been said, also, you Need to get dimensions of your
FF case I.D., Freebore length and diameter, Leade dimensions and the groove and land diameter of the rifle in order to get a proper fit of the bullet, along with the paper thickness. A chamber cast is the best way to get all that.
beltfed/arnie

Arnie will most likely chime in again but he taught me somewhat how to get a dual diameter bullet to shoot best by giving me tons of advise here on the forum as to why he was doing what. Basically, the nose riding section is easy as you want the patched bullet to be snug but not tight.  The trick part and why my bullet probably won't work in the next guy's rifle is that the length and diameter of the freebore area of the chamber vary.  Then there is the fired case inside neck dimension.  Ideally, you start with a barrel blank and have it cut with a proven chamber but us guys shooting for fun most likely buy a rifle ready to shoot.  A chamber cast must be made to see how long and what diameter the freebore is.  That is the diameter I think you need to strive for.  So for instance if the bore is 0.408 and the freebore is 0.410 and 0.300 long, then you specify a dual diameter with the base section 0.400 long or a tad longer that will patch to 0.410.  If the moon and the stars line up, that diameter will allow you to load a pp bullet without resizing your case and be a slip fit finger seated.  With black powder the powder and wad column keep the bullet from going in to deep.  Now I know nothing about sizing patched bullets but I think Arnie does.  I just wrap mine as cast and let fly, but I am happy with a group that the big boys would never be satisfied with.  My path has often been frustrating but I can now shoot groups that rival my gg bullets.  The one thing for sure is that paper patching has kept my mind and trigger finger busy during these pandemic times.  Have fun.  Tom

BE Tom,
You did a good job of describing basics of need to do the chamber cast and then fit the DDEPP bullet "patch to" dimensions to the chamber. As said, important to fit the base band/major diameter length and diameter to the FF case I.D./ and Freebore diameter, along with the length from the seated depth in case to the end of the freebore. 
The body diameter will be such as when patched it comes to a slip fit on the lands.
beltfed/arnie

It is something that is new and different but not as hard as it sounds.  The key is fitting the bullet to your rifle and a chamber cast will give you everything you need for data.  I had never done a chamber cast and was frightened but it is easy as pie.  Arnie can post pictures of ragged one hole groups and after several changes in my procedures I can shoot 5 shot groups into 1 1/2" at 50 yards consistently in my 40-70 Hepburn with iron sights.  That is about as good as I can see and with gg bullets going into 1" at 50 yards.  Tom