Mick,
If I can presume you have a typical 40-65 "grease groove"
chamber, probably with some freebore, I can recommend
a Dual Diameter pp bullet such as mine, as shown in the attached pic. The concept is growing with a number of people going that way.
Idea being you have a base band that patches to your
Neck I.D. /freebore /groove diameter, and a "patch to bore"
body that loads on to the lands.
My DDEPP (DualDiameterEllipticalPP)bullet for my 16 twist 40-65 is 370 gr, 1.325" long and loads over 75 gr of Swiss 1.5 powder for 1400fps. It is stable and accurate even to
long range.
Another friend had a stretch version at 1.44" cut by brooks
for his 14 twist 40-65. Its working very well now.
Suggest you do a chamber cast to get exact dimensions
so as to get the right diameters/ base band length for your chamber . 
beltfed/arnie

Mick,
I would be happy to send you some of my DDEPP bullets
for 16 twist 40s.  PM me your interest to try them.
beltfed/arnie

Arnie
Thank you for your kind offer, but for the moment this idea is in the early stages of consideration, and may not proceed until I am in possession of all the facts and possible costs.

Randy
I just looked up the swaged bullets on offer from BACo and it seems that they do not have one suitable for my experiments in the size range I require, ie, they have a .365" bullet and the next size up is .395" which would be too big.
I miked the onion skin paper and it was .0022" as near as I could tell.
As mentioned before I was hoping to avoid buying a mould just to try an experiment. Arnie kindly offered to send me some of his bullets, but with the cost of postage being what it is I'm reluctant to accept his offer.
I should probably do a chamber cast as well, CPA chambered the GM barrel for me and I no longer have the reamer dimensions in my computer. 
What I do know however is that when I got the barrel back a  45/70, case when sized in my Lee 40/65 FL sizer, would not chamber, and I had to use a friends cut down 40/65 sizer to get a case that the action would chamber, and eject.
After firing the neck has expanded to an ID of .410" and my .409" Money bullets are a loose slip fit.
Having said all that the rifle is quite accurate and will shoot between .800" and 1.5" at 100m on any reasonable day using BP and wiping between shots.
I was just curious as to what accuracy improvements might be gained by trying paper patching Vs greasers.
Mike.

There are a number of ways to shoot patched in a so called grease groove chamber.
The problem with BACO's swaged bullets is they are dead soft lead and that doesn't make for the best in accuracy.
I have good results with the 396 415m bullet cast from 16-1 and wrapped in Seth Cole 55w paper, in a couple of 40-65's one of which was a CPA. The other bullet that works decent in all the 40's lounging around here, is the .400 360 that BACO offers, it works when cast from 20-1 or 16-1 , again wrapped in Seth Cole 55w. You do need to seat it a bit deeper to get it to chamber, but that doesn't seem to present any particular problems.
Accurate paper patch shooting is probably more dependant on a good wad stack, and fouling control.
Yes you do need to resize cases for some chambers using those diameter bullets, but I guess I've never been so lazy that resizing cases presents much drudgery.
If you do start down the paper patching trail, you can save a lot of grieve, by starting you're powder charge at 2 gr. more powder than the same weight/design of the greaser you're now shooting.

Been shooting dual diameter patched bullets in the 44's and 45's since before they became popular, matter of fact I remember being told they would never work.... Having said that, some rifles get along well with them some don't/won't.
I have a new dual diameter 40 cal mould on hand, so far it's doing alright , but nothing to particularly crow about yet.
Anybody that crimps a patched load by any means is just asking for trouble. Good neck tension is the best way to go. Many resizing dies take a case down far enough to give good tension on a patched bullet. Case mouth's should be inside chamfered from time to time. I have never annealed a case used for paper patch loads.
Nice simple wad stack you use, not much different than what I use, only I do put a felt wad under the bullet.

Blackpowder
Thanks for that, looks like the BACo swaged bullet will work at a patched diameter of .400".
As a matter of interest how did they shoot in your rifle compared to greasers ?.
One comment made on this subject said that the BACo bullets were swaged from pure lead and may be too soft to work well.
Actually I was under the impression that originally most of the PP bullets were just plain lead in not a mixture of lead and tin.
Anyway as things stand I might try BACo for the bullets if they are prepared to post them, the reason I say this is because they will not post brass for some reason, maybe bullets are OK.
Mike.

MickB, some of the original patched loads were indeed pure lead, some were 16-1 and some even as much as 11-1.
You apparently aren't in the US? as there is no problem getting brass from BACO, outside the US then export laws start taking hold, and it does become a problem sending brass and bullets overseas or even across the border to Canada.