I thought about a rifled barreld pistol and rifle that used 410 cases with a protruding bullet. I started a thread on it a year or so ago. its doable but a 410 rifled pistol shooting shot would be next to worthless except in a very close quarters situation. IMOO. it would likely not be very accurate in 454 lc or Casull with all the free bore and chamber issues to make it accept the 410 shell. a 444 marlin pistol would be better and you could load shot into those cases if you had the desire to have a SG round. 444 marlin is almost 2.5 long so you could nrarly equal a 2.5" 410 round.
Im still trying to get time and money to finish the 444????? project.
Im planing on a 3" chamber 410 barrel on my switch barrel build it would be pretty easy once the bugs are worked out to make a identical barrel except rifled and run .44 or 45 bullets protruding from a brass case like a normal rifle round. check out the 12 guage SGFH in the general discussion. it would be like that but a mini SGFH. it would be pretty damm close to a 45-70 also in power as well. a rimless wild cat would be doable and then factory bolts opend up slightly would work. a rimless 410 shell can be made from 30-06 or simular brass BTW.
there is a poor mans big bore there some were and it would have the case capacity to blow the doors of the the 450 bushmaster, 458 SOCOm and likely the 50 beowulf.
I have been looking at 284 win brass as well as 7mm mag brass for a possable 450 wild cat Shotgun round as well it would fall between a 410 an a 28 guage. wads would be a issue possably the 458x2" is doable as well. the lug spacing gets pretty tight on the magnum brass and it wont clear. it would be doable on 308 Sagia however. Im not sure if .284 brass will clear the lugs but it might.
Its all doable with money and time.