Interesting data on 110 FMJ effectiveness

[INLAND44]

Whatever, a 110 gr .30 caliber roundnose FMJ, soft point or semi-jacketed hollow point (Speer #1835) at 1950 fps is a serious round for a pistol-caliber carbine. 5.56mm NATO has too much penetration potential in my suburban environment to consider firing it inside the house. For those times when a pistol isn't enough and a shotgun may not suffice either, the .30 Carbine is very attractive. Particularly in a sub-gun, its a serious chopper. The Israelis still use a 'bullpup' M1 Carbine sub-gun in some security forces. But even in a semi-auto, .30 carbine is devastating at 100 yds or less, particularly the hollow point. Now an AR15-type in .30 Carbine would be very cool to me. Such a gun was once made by Olympic but didn't sell, so they dropped it. I think a conversion would be possible using a chamber insert in a 7.62X39 barrel. You would use a standard bolt. The magazine would consist of basically a 5.56 mag as the outer shell with a carbine mag inside, shimmed correctly to feed. But I digress; a factory-made one would be preferable, of course.
I no longer have any tactical applications in mind for my one M1 Carbine which is in preservation mode, but an AR or other carbine, even a High Point in .30 Carbine would get my attention as a home defense gun.