Terry, I have an Idea you are resting the double dirrectly on the sand bags to try to get on target. That is a NO NO! A double rifle depends on the proper recoil swing as it does when fired OFF HAND! The rifle should never touch anything but your face,your shoulder, and your hands when being fired. Addtionally, the rifle should be fired from cool barrels, in a rt, lft, rt, lft, sequince for a four shot group. Then barrels should be allowed to cool back to ambient temprature before the next group. The rifle should be held as if shooting off hand, because the right barrel will normally recoil up, and to the right, and the left barrel will recoil exactly the opposite, and should be held in your hands. It is OK to rest your fore-hand on the bag, but hold the fore-stock in your hand, and do not rest the butt on anything. The speed, and recoil of the rifle is what makes the bullets hit at a particular place on the target, and absolutely must be allowed to recoil as when shot off hand, sitting as streight up as close to the way you are when standing as possible.

Try to find a large sheet of cardboard, place it at 50 yds and put a "T" shaped aiming point in the middle, and hold where the verticle intersects with the horrizonal, and no matter where the bullets hit hold the same for all four shots, marking them on a sheet of paper RT#1, LFT#1, RT#2, LFT#2. This will tell you something about what the rifle is trying to do. If the Rt barrel shots are on the right, and left barrel shots are on the left, and in this case the group will usually be HIGH, and the grouping is because the barrel time is too long,( bullets are too slow,or the bullet is too heavy). It the Rt barrel shots are on the left, and the left barrel shots are on the right, and all shots usually low, then the load is too fast, or the bullet is too light!

I wouldn't give up on the double too quickly. You wouldn't believe how many very good double rifles I have bought at bargain basement prices, because the owner thought something was wrong with his rifle, and he laughed while walking away with a little money, while I was laughing because I got a good double for half price. All this simply because he did not know how to load for, or shoot his double rifle.