Remember they did the N frame in .30 carbine. I suppose you'd like to do a 586 or 686 in .30? Problem will be the overall length of the cartridge compared to the cylinder. Lining a barrel won't be magic, not sure what your end result of the cylinder will be, the closest I've done was a Webley down to .22. I must say the theory was sound, but the practical application didn't work that well. I'd think if you're bound to make liners, the larger caliber would be easier. Say...45 Colt? Then you have room to work...the weight might be worse but you can reduce the barrel a bit and move the front sight back a bit. A 3" pipe would be sweet. The flash will keep your Beardicon from getting too long too...your ejection will need some thought. You'll need to look at the 547 in 9mm. You could make some half moon clips, or maybe modify the .357 full moon clips for N frame guns.