At HD distances M193 velocity from a 16" bbl is adequate to produce reliable and substantial bullet fragmentation in soft tissues.
In the event of an errant bullet, M193 is not barrier blind. Walls are hard barrier materials that present shear force resistance to bullet penetration which causes M193 to fragment.
I had a longer reply but thanks to Murphy and his law I lost it all. Cliff's notes:
Read these pages:
1. Contrary to what we have been told, XM-193 does not seem to "fragment" when shot into drywall walls. After we were through for the day, we even shot several more rounds of XM-193 into the walls to see if we could get one to fragment. They did not.
It is clear that they were tumbling and deviating from the flight path, but they were still penetrating the walls.
Now, before anyone says it, No, I do not know how much damage they would do to someone after the 4th wall. But they would do some damage as they were still penetrating.
2. Remington 55 grain JSP and Frangible 5.56 also penetrated all 4 walls. So did the .30 Carbine.
When shooting rifles, walls are concealment, not cover.
Things to take from this:
- There are no magic bullets that stop bad guys without penetrating interior walls
- Bullets designed primarily to fragment in walls are not as effective as bullets designed to stop a threat
- Knowledge of your equipment leads to confidence, confidence leads to less stress when depending on your equipment.
I'm not condemning your use of XM193, it's my go-to round if I run out of soft points. Just understand you still need to be aware of what is beyond your target, even behind interior walls.