I keep #1 buckshot alternating with slug in my 12ga shotty. :shock:
The reason for the #1 buckshot? 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.
It's a tad more expensive and a little harder to find, but Cheaper than Dirt and some other places sell it at reasonable prices.

For further info: http://www.firearmstactical.com/briefs10.htm
The reason for the #1 buckshot? 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.
It's a tad more expensive and a little harder to find, but Cheaper than Dirt and some other places sell it at reasonable prices.
For further info: http://www.firearmstactical.com/briefs10.htm