Dave,
Now the .46RF Ballard- This rifle is a bit confusing. The chamber dimensions are between the .44RF and the .46RF and the bore is .430 inch diameter. So, for this one, I am cutting down and fireforming .303 British cases. I am still playing with this as I have to fit a CF firing pin to the block without butchering it (it is dated 1864).
I looked up cartridge dimensions in "2nd Edition, Ammo Encyclopedia" by Michael Bussard.
The 44RF series is listed as having two different body diameters: The 44 Short Rf and 44 Henry Flat RF at .445" and the 44 Long RF and 44 Extra Long at .458". Bullet diameters are listed as .446" (Short, Extra Long, and Henry Flat) and .451" (Long).
The 46RF series is listed as having .458 body diameters for all four members (Extra Short, Short, Long, and Extra Long).
Bullet diameters are listed as .454" (Long) and .456" (Extra Short, Short, and Extra Long).
None of these seem to have a bullet intended for a .430" Bore.
What is the Groove diameter of the 'Ballard' Barrel?
Perhaps a measurement of the chamber length (a chamber casting?) would help sort out the correct cartridge dimensions.
Your Experiences with the .25ACP and .25 Stevens seem to parallel my own as i am also experimenting with Lengthened .250ACP cases and .25 Stevens "CF" conversions of .22 Hornet cases (reforming the Hornet to .276" body diameter down to the rim and trimming to various lengths from 1.000" to the limit fo what is available after the body diameter is 'swaged' down.
I have been considering using swaged down .014" wall model Hobby tubing to .276" OD and Temporarily holding the blanks either by tension or with some 'glue' but I have not tried to fire any yet.
Your CAUTION Warning about the tubing going with the bullet into the bore is good advice.
The .25 Stevens barrels I have all seem to have steps in diameter at the 'bullet end' of the chamber that the tubing nominally would seat against, something like happens in a .30 M1 Carbine or .45ACP chamber both of which head space off the cartridge mouth.
I also have purchased a Barrel Blank to be made into a .25ACP rifle length Barrel eventually for a Marlin Model 56 Action but as an interim will be worked up as a full diameter 'Bull Barrel' for a Stevens Favorite Action to run my Experiments with. It is from Lothar Walther and is properly sized (bore/groove) for the .25ACP/6.35 Browning) rather than the larger .257" of Rifle bullets and cartridges. Nominal Bore/Groove are .243"/.250" with a 1 turn in 9.4 inch Twist rate and a 23.4 inch length.
For my .32 Caliber experiments I have recently received a Shelin Match Grade Stainless Steel Barrel Blank of 28-1/8 inch length and 1-1/4 diameter that measures .301 Bore and .308 Groove diameters. It will also be worked up as an interim full diameter 'Bull Barrel' for a Stevens Favorite action. i have several used Stevens .32 Long barrels in various conditions of bore and exterior with one notable because the chamber diameter measures .348", way over even .32 S&W Long case diameter, let alone .32 Long Colt or .32 Long RF diameters. But it slugs suitable for .32 Long Colt so I will probably have it fitted with a Chamber bushing and reamed to 'match grade' .32 Long Colt dimensions.
My own inventory of Cartridges I load for include .25ACP, and my Experiments, .25 Stevens (RF and my CF Experiments) .30 Carbine, .30-06, .32 Long/.32 Long colt, 38 Long Colt, 41 Long colt, .44-40WCF, 45ACP, and .45 Win. Mag.
Your range of firearms in RF, and Cf versions of the same, is very impressive, I am glad you decided to share your experiences with us.
Best Regards,
Chev. William