I think Randy Wakeman makes a good argument for #1 and/or #0 Buck for HD...
http://www.chuckhawks.com/home_defense_shotgun_ammo.htm
12 or 16 projectiles penetrating 12" to 14"
http://www.chuckhawks.com/home_defense_shotgun_ammo.htm
12 or 16 projectiles penetrating 12" to 14"
The Firearms Tactical Institute reports:
"Number 1 buck is the smallest diameter shot that reliably and consistently penetrates more than 12 inches of standard ordnance gelatin when fired at typical shotgun engagement distances. A standard 2 ¾-inch 12 gauge shotshell contains 16 pellets of #1 buck. The total combined cross sectional area of the 16 pellets is 1.13 square inches. Compared to the total combined cross sectional area of the nine pellets in a standard #00 (double-aught) buck shotshell (0.77 square inches), the # 1 buck shotshell has the capacity to produce over 30 percent more potentially effective wound trauma. In all shotshell loads, number 1 buckshot produces more potentially effective wound trauma than either #00 or #000 buck. In addition, number 1 buck is less likely to over-penetrate and exit an attacker's body."