Kudos for the good work, brobee; your results mirror what Dr. Fackler had to say concerning the effects of #1 buck:
12 Gauge Shotshell Ammunition
For personal defense and law enforcement applications, the International Wound Ballistics Association advocates number 1 buckshot as being superior to all other buckshot sizes.
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.
For home defense applications a standard velocity 2 ¾-inch #1 buck shotshell (16 pellet payload) from Federal, Remington or Winchester is your best choice. We feel the Federal Classic 2 ¾-inch #1 buck load (F127) is slightly better than the same loads offered by Remington and Winchester. The Federal shotshell uses both a plastic shot cup and granulated plastic shot buffer to minimize post-ignition pellet deformation, whereas the Remington and Winchester loads do not.
Second best choice is Winchester's 2 ¾-inch Magnum #1 buck shotshell, which is loaded with 20 pieces of copper-plated, buffered, hardened lead #1 buckshot. For those of you who are concerned about a tight shot pattern, this shotshell will probably give you the best patterning results in number 1 buck. This load may not be a good choice for those who are recoil sensitive.
Third choice is any standard or reduced recoil 2 ¾-inch #00 lead buckshot load from Winchester, Remington or Federal.
If you choose a reduced recoil load or any load containing hardened Magnum #00 buckshot you increase the risk of over-penetration because these innovations assist in maintaining pellet shape integrity. Round pellets have better sectional density for deeper penetration than deformed pellets.
Fourth choice is any 2 ¾-inch Magnum shotshell that is loaded with hardened, plated and buffered #4 buckshot. The Magnum cartridge has the lowest velocity, and the lower velocity will help to minimize pellet deformation on impact. The hardened buckshot and buffering granules also help to minimize pellet deformation too. These three innovations help to maximize pellet penetration. Number 4 hardened buckshot is a marginal performer. Some of the hardened buckshot will penetrate at least 12 inches deep and some will not.