Gun enthusiasts or gunsmiths, would fallouts pipe weapons really work?

So playing 4 and especially 76 I've never really looked at pipe weapons. However recently I made a Bloodied less ap cost pipe rifle for my rifleman build and I've been taking closer looks at the gun itself and wondering if it would actually work.

I've seen Brazil and the Philippines make some insane homemade firearms but nothing like the pipe rifles. Plus most of them I've seen are .22lr and maybe 12 gauge here and there.

I'm not asking how to build them, but simply the pipe rifles we do have, base game would they work? Or what would need to be changed or tweaked for them to work?