I've just developed a hankering for a 20 gauge rifle, after reading the article in the Autumn DGJ. What I have in mind is to get an accessory rifled 20 gauge barrel for my New England Firearms single shot break-open rifle. I know that I could just use rifled slugs, but I'd prefer to load my own and use paper or brass cases and cast lead conical bullets, probably paper-patched, and load it like a rifle. I may use black powder and smokeless as well. I'd like to hear inputs about cases, bullets, wads, powder, reloading dies and loading data. Will the thin Magtech brass cases work, or are there thick-walled brass cases available?

My only comment is to look carefully at the rate of twist on these rifles. They are made to shoot sabots I believe. I made a rifle similar to this using a hasting barrel liner in a break open british 12 bore. The 20 ga rifle I made shoots excellent, though I regulated it for Lightfield (saboted)slugs. Good Luck,
Steve

Brass cases will be too thin unless you get the machined ones. Rem plastic cases worked for me in my 20 ga paradox. They grip the bullet well so you don't have to worry about crimping. For load data, look at loads for the same weight of shot. The conical bullet I use weighs right around 500gr (it's the WR design for their fauneta). You will have to put some felt wads in the case to take up the space. I also used plastic obturator wads just to be sure of getting a good seal. Thus loaded, this gun is WAY more gun than a 20ga foster slug. Waaaay more.

Been there tried that with the NEF.
That twist is fast and you would need a very heavy (or long) bullet to stabilize well in the barrel (I calculated upward of 900gr). I shot up to a 515
Rem cases are probably the best to work with as they seem to give the best fit and roll crimp well. They also gave higher velocities and lower deviation. I believe that the groove was about .625 or so in the NEF barrel and the Magtechs are too thin. The proper twist seems to be about a 60" or so with reasonable 400-500gr slugs in the 20 if they were a standard conical design. Rem SP20 wads have a very wide base and act as a good seal

Tom