This subject seems to come up quite often on Internet forums. Recently I saw it again and thought that some basic information might be helpful to shooters who have this question.
If I had to answer the question with one word it would be a resounding "NO"!
Shotguns are shotguns and pistols and revolvers are...well you know the answer. The question and the subject have been blurred by the fairly recent development of revolvers like the Taurus Judge series and the S&W Governor line.
A lot of R&D time was spent on both of these revolver lines, not to mention the approvals necessary, and none of that should be taken lightly. Firing shotshells through rifled barrels and being able to hit a target at 21" is no small accomplishment. Getting BATF approval for what could be considered a short barreled shotgun is not either.
Both Taurus and S&W should be applauded for their efforts and tenacity.
Maybe this will help some.
Most .410 bore shotguns are not proofed for the pressures generated by the .45 Colt cartridge. The maximum chamber pressure for standard .45 Colt is 14,000 p.s.i. and for the .410 bore it's 13,000 p.s.i.
It should be noted that there are “modern” .45 Colt loads that do not follow the conventional restrictions placed on this cartridge, using the old black powder standard, and these “new” .45 Colt shells can develop much higher chamber pressures.
Chambers on guns can vary in inside diameter.
For example, the Taurus Public Defender Ultra-Lite that I carry has a chamber diameter of .485.
The .410 Springfield Model 944 that I use as a control for evaluating .410 loads, has an inside chamber diameter of .475.
Here are some outside diameters of various shells:
Remington Express Long Range (made for shotgun use): brass .470 - hull .470
Remington UHD handgun: brass .470 - hull .443
Federal Personal Defense handgun: brass .470 - hull .449
Winchester PDX1 handgun: brass .470 - hull .445
All of these shells use some form of brass that allows them to expand and fire form to fill the chamber area but also allow a relatively easy extraction. Some makers have attempted to use steel with a brass or other finish and while the steel with expand, it will not allow easy extraction. You won't find those shells on the market today.
Barnes Vortex: brass .473 - bullet (projectile) - .440
Winchester CA: brass .475 - bullet (projectile) - .432
These cases will also expand and fire form to fill the chamber area.
As can be seen there is a "variety" of outside diameters in both the shotshells and the .45 Colt cartridges.
It should also be pointed out that it was the inside diameter of the chamber of the Stevens shotgun that was cited above. That particular shotgun has a fixed full choke and the inside diameter of the muzzle is .396, considerably smaller than either of the .45 Colt bullets that were mentioned. So, even if the chamber remained intact, after firing the .45 Colt cartridge, the results of the bullet encountering the reduced diameter of the bore at the muzzle, or before, could prove to be a disaster.
So, should you shoot your .45 Colt (.45 Long Colt) shells through your .410 bore shotgun?
No, it's unsafe for all the reasons stated above.