Hey Cool, Last year after the season I did a survey on just this topic. I am a die-hard duck hunter here in Maryland, hunting in very heavy marsh conditions with 12 ga and every variable of shot size and shell size. Even with the help of 2 dogs, we were still leaving a lot of wounded birds behind. Even if the bird can't fly they can dive and out fox the best of dogs and man. I was steered to the SP10 Remington 10 ga shotgun and to reload my own shells. Hear me out first. I have a full study being compiled that I will publish on this site soon that incorporated over 200 hits and 48 over responses. Including info received from other web sources and what limited supply of Mags that are out there on the market. The proof was shown to me on paper and then first hand by me this past weekend. The cost of set up did not set me back and the product delivered was just what the doctor ordered. One shot one kill, no wounded. I loaded the 10 ga with #1 shot, which is the optimum size shot for maximum performance and lethal kill power for that gun for both ducks and geese. Reloading was a breeze even for the novice IF you read all the info, stick to all the steps outlined and respect the process. I also recommend you get a coach for support, very helpful in your decision process. The SP10 was flawless. I was covering my buddies (they were using 12ga's) for the final kill shot. Again they were hitting the birds, you can see that but they were flying wounded to the ground and that’s when we would lose them in the heavy marsh. My birds were dead in the air before hitting the ground. All it takes is 1 pellet to bring a bird down, its just the kill velocity and penetration that is needed to do it successfully. My birds were hit with 3 to 5 pellets and not torn up but very clean entry and exit sites. I can send this info direct to you if you request it. Even if you want to keep with the 12 ga I recommend the #1 shot is the best overall shot size for both ducks and geese and get into reloading your own shells. Good hunting.