mudpack wrote:Since max killing range of a shotgun is solely determined by pattern quality, the 3's should deliver a killing pattern further out than 2's will.....ALL ELSE BEING EQUAL.
And, since max killing range of a shotgun is solely determined by pattern quality, a heavier payload should deliver a killing pattern further out than a lighter payload.....ALL ELSE BEING EQUAL.
Get my drift?
I understand what mudpack is getting at, but this is a bit of a misleading statement. If this were completely accurate, then we'd all be shooting steel 9's and killing ducks at ridiculous ranges.
Load choice necessarily involves a trade-off between pattern density and penetration.
Shotguns work by putting one or more pellets through a vital organ (brain, spinal cord, heart, lungs, major blood vessel, flight bone, etc...). Only about a third of the bird's body is vital - hitting it elsewhere (legs, abdomen, tail, etc...) only results in a wounded bird. As mudpack correctly pointed out, you need to hit the bird with enough pellets to ensure that at least one of them hits a vital organ and puts it on the ground. Generally 4-6 hits are enough to ensure this takes place.
The other issue is penetration. An experience I had will help to illustrate. In the early days of steel shot I hit a fat late-season mallard crossing at about 40-45 yards. It was a shot I'd made hundreds of times with lead. Feathers flew, the bird was rocked, but he kept flying over a ridge and out of sight. Luckily, a passing trucker saw my bird go down and retrieved it for me. I decided to do a necropsy on that bird. He took at least three potentially lethal hits from #3 steel pellets (so no issues with pattern density). Two of them penetrated the thick feathers, skin, fat, and were embedded in the surface of the breast muscle - they did not have enough penetration to reach the vital organs. The third pellet hit right in the armpit. It also did not penetrate very far, but it did cut the brachial artery at the base of the wing and the bird bled out from there (there was a clot of blood the size of a golf ball around that hit). Luckily, the current crop of steel shotshells are much improved, and I wouldn't hesitate to shoot that same duck again with a modern 1400+ fps load of steel 3's.
To answer the original question, there isn't a huge difference between 3's and 2's. At the same starting velocity you get similar penetration about 5-7 yards further with the larger pellets. As long as you are holding adequate pattern density, you will see some improvement with the larger shot size. However, you likely will need a tighter choke, and will give up some pattern width at shorter distances. All part of the tradeoffs with shotshells. In order to make the best decision, you need to look at your individual circumstances. If you are pass-shooting big mallards at 40-50 yards, the faster load of 2's shot through a tight choke would likely be better. If you are shooting multiple species over blocks at 20-40 yards, then the slower load of 3's (with an open choke) may be more appropriate.