I'll agree with light 8's for a beginner. The "light" part is the key. I don't really see much difference between 7 1/2s or 8s, but will use the 7 1/2s at longer yardages. 1 ounce 8s are what I use for almost everything out to 22 yards or so. I'll use 3 Dram 1 1/8 oz of 7 1/2s beyond that.
As you know, you can not always get 1 oz loads at WalMart. Use the 3 dram 8s at 1200fps. They will break targets consistantly all the way to the 27. If they are out of 8s, use the 7.5s. there is no realistic difference between the two sizes and you should NOT GET HUNG UP on 1 particular load or brand. Please note that the Winchester Universal 8s actually measure 8.5, and their 7.5s spec to 8s. You can use a more open choke at 16 and still get great pattern density because there are more pellets in the Universals. The Federal shell's shot are what they say. The Universals burn dirtier. If you are a slob that seldom cleans your gun, buy the Federal.
Now, the tip of the week. As a new shooter, it doesn't matter which size shot you use as long as you use a lot of it. Practice is what will make you better.
I don't know where he's from but, should'nt he use 7.5's in the winter and 8's in the summer? These new Bio-targets are tougher when cold. Probably an old wifes tale but just thought I'd mention it. Dave T.
gunnertom, once you are breaking 23, 24, 25 almost all the time, shot size might have reason to drift into your mind. Until then, it's just one more thing to get diverted by and make some unsupported decisions about.*
Shoot lights. That 2 3/4 "dram equivalent" or under 1150 ft/sec if you shoot 1 1/8 oz. loads. If one ounce, and there's no reason not to, then a little faster is OK. But not much faster or you are not getting what you are after, reduced recoil.
Just buy any light shells.
* So what's wrong with a few unsupported decisions, you ask? Well, say you begin to suspect that 8's are "best." And then have to shoot something else and miss an extra bird or two. You will be inclined to tell yourself "It must have been the shells." It wasn't; it was you, and you've passed up a chance to look hard to see what it _really_ was. Mostly, it's just chance anyway, but even that is _well_ worth knowing, probably more worth knowing than what's the best shot size, if any.