Could a person if pressed use Black Hills blue box 55gr FMJ for home/Zombie defense out of a 14.5 inch M4A3? Say a FUBAR riot strikes and you had no M193 but plenty of the above ammo do you think you could still be effective 100 yards and in with the BHBB ammo? Or would you be better off  shooting "spit wads"?

it's better than nothing, I've never had a problem with it, and I have nothing but good things to say about it. I wouldn't have it as my first choice of defensive ammo, but if you had to.

Very expensive reloads, but they go bang everytime........so Yes

I don't think it would be that bad of defensive ammo at all.  

Man, I would be using wolf ammo for SD if that was the only ammo I could find.  If I had to choose the ammo I would carry into battle, I would choose something different but I would use anything in a pinch

if you are saying if you have to use it then yes if it goes bang and you can put holes in people then it will work. But all you have to do is read one of the tacked threads and see what we would rather carry.

I think you asnwered your own question by the words, "if pressed".  If pressed, anything you have on hand that goes bang in better than a sharp stick.

Please do yourself a favor and read some of the threads on this forum and then try to stock up on what you feel would be "more effective" than your practice ammunition.

While most people who even think about the idea of having weapons and ammunition on hand for SHTF incidents store a sizeable amount of ammunition on hand, in reality, most incidents will be settled in a magazine or two. (though this is one of those times that it's better to have extra!)

Not everyone can afford to run out and buy 10,000 rounds of ammuntion to stass for a rainy day.  But if you buy alittle at a time, on a regular basis, you'd be supprised how fast your ammunition stash can grow.

Beat Trash

I'd use 22 Short if that's all I had.
And with people 100 yards away, I'd hope I could get at least a couple shots into them before fixing bayonets.

Any ammo that went "bang" more than it didn't and managed sufficent velocity to get to the target would be useful if that's all you had.

There's nothing wrong with 55gr (M193-type) ammunition in a 14.5 inch barrel.  You just lose some range in the "guaranteed fragmentation zone."  Basically, the round will still make holes and still tumble through the mechanism of the "change in medium," i.e. air to zombie body.  But the fragmentation of these rounds would be reliable at less distance than if you fired them out of a 20 inch barrel.

Considering that the bullet WILL tumble-it's a spitzer, it must tumble when it changes media-then I don't think the fragmentation thing is that big an issue.  The zombies won't care.