I built a 605 clone, this one is a dedicated .22 using a Spikes barrel. Since the chamber is deeper in the upper receiver, it's the original overall length with a 16" barrel.Lower receiver is late, but it's close enough for plinking.
I'm somewhat surprised there isn't a sub-forum or at least some discussion on this subject. I like shooting blackpowder, but haven't in a while. I traded into a flintlock .45 rifle and have yet to fire it.
Here is a dedicated .22 I built as a 605 replica carbine. I used a Spikes 16" barrel, Ciener kit that was made for the Spikes, A modified M16A1 upper, and original furniture. I use Black Dog 25 rd mags .
Refugee from Oregon, bought a house in Apache Junction, I'm loving it here! Looking forward to getting involved here. From antiques to ARs, I love them all.