Home Defense Ballistics

[vicious_cb]

Understood. I should've clarified: I'm not looking at overall performance, but rather, the niche application of home defense in an urban environment.

If you wanted an absolute niche round for urban environments then Id pick these 2, but thats neither here nor there:

Colt MARS



6mm KAC PDW

[MegademiC]

Bullet construction is more important than weight.
62gr fusion is a great round.
77otm tends to penetrate less than 62gr m855
155gr vmax 308 penetrates less than 62gr fusion.

[vicious_cb]

Interesting.

Unfortunately, it looks like neither the Colt MARS (aka 5.56x30mm MARS) nor the 6mm KAC PDW (aka 6×35mm PDW) are widely available.

Moreover, it sounds like the consensus is that the only real (commercially viable) alternative to 5.56x45mm is the 5.45×39mm, but since the former is so cheap, reliable, and ubiquitous, I stand to lose more than I'd gain in going after another caliber.

Thank you all, again.

No they are not. The Colt MARS is experimental and the KAC PDW round would probably needed to be contracted in the 10,000's/year for them to even sell it to you.

But these are what I think represents the best round for the 0-200m fight. The closest you can get to these cartridges commercially is the .221 fireball.