Hello to you guys, (I mean the three last persons that answered my post).
Here are some of my thought regarrding the subject:
If you are willing to use 45 acp, that is fine, the round is subsonic, the rifling twist is perfect for the 230gr bullet, the choice of bullets is great. Only ploblem, except the marlin rifle, and a few others (I have seen lee-enfield actions converted to take colt mag and feeding reliably, like a deslisle), your options are going to be prety limited to single shot . The contender barrel would be great for that purpose.
If you are going the contender way, than a barrel in 45 long colt is the way to go because you can launch heavier bullets(in the 45LC range) that WILL stabilise properly because the twist and the weight of the bullet MATCH.(twist in 45LC is arround 1 in 14 or 16 if Iam right).
Now if you had a barel in 45/70,here are the problems that ocur: the twist for that caliber is quite often 1 in 20, which is good to launch heavy bullets(400grains for exemple) at super sonic speed. But these same bullets would not stabilise at subsonic velocities in the same barrel.
So a barrel specialy made with a twist of 1 in 12" (more or less) would help to stabilise these bullets at subsonic speed.
Now, I do not like lever action either.
So I would go for the bolt action option.
I do not like beleted cases and rimmed case in a bolt action (also the belted can work very well).
I think that the ideal shape of the case would be a rebated case that would fit a standard bolt action face(.308), that would have a small case volume, similar to a 45 LC, a shoulder (20-25 degres for exemple) for reliable feeding, a good long neck to help hold these big long bullets (case neck lenght> bullet diametre).
Now I am not trying to reinvent the 458 socom, but almost. A 284 winchester case, shortened would be the idea, specialy with all the good quality brass available from lapua and hornady in 6.5x284.
There is another case similar to that idea called the 45 blaser. but its capacity is to large, it is design for supersonic speeds. but is gives an idea of what it would looks like.
have a look at :
http://www.municion.org/45blaser/45blaser.htm
Of course, that baby needs a special reamer, a special set of dies, a custom barrel... etc
But having spent a lot of money in another projet in the past ( ruger 77/44, with silencer) and not obtaining the good results Beacause the twist and quality of the barrel where not up to it, made me think.
Let me know what you think.
ND