DA Revolver carbine...

The way of measuring barrel length for legal purposes is from muzzle to breach face. By contrast, revolvers, by way of tradition, when stating barrel length typically only include the rifled section, not the chamber.

So, if we wanted to we could make a revolving carbine with a barrel such that it measured 16" from muzzle to breach, and having no action length to speak of, we could have a VERY compact, short, and light carbine packing 7-8 rounds, with a good rate of fire, easy reloading, and not sensitive to COAL, or projectile style, or power level, and able to shoot both .38 and .357.

For home defense you'd have all the good points about a revolver but with less jurisdiction specific legal restrictions (handgun vs. revolver) and more power, less flash, blast, & recoil, and easier to hit with.

If they used titanium, aluminum, or scandium, they could make it ridiculously light.

TED

The contrasting perspective:

- Likely ALL of the cost of a viable rifle-caliber carbine (if done properly and with materials you describe)
- Eventual timing issues associated with a revolver
- Quality .357 ammo rivals rifle ammo prices
- Long, DA/SA revolver style trigger is not going to be popular for a carbine.
- Likely awkward stock design and ergos

I've still got the 94AE Trapper in .357 that was the first centerfire my family owned. It's a sleek little gun and pretty cool in .357, but performance/use wise (mostly due to the round), it's sorta pointless. It will print tighter groups than its pistol counterpart 25-75 yards, but gets its ass whipped compared to any rifle caliber carbine. Yeah, it's small and handy compared to a real rifle, but there is a rather large weight/size penalty compared to that of say a 6" revolver (in the hands of a decent shooter) that there really isn't much point to it.

A break-down backpacker kit that could dispatch medium size game...that's probably what would make the most sense, but that's a tiny, tiny niche.