When I bought my 1941-vintage L.C. Smith, it was choked modified and full, as many doubles built in the old days were. I had its chokes opened up to skeet (.005 inch of constriction) in one barrel and modified (.010 inch) in the other. I shoot that gun quite well, and I absolutely love it for hunting everything from quail to pheasants.
The 2 1/2-inch field loads offered by several companies with Nos. 4, 6 and 71⁄2 shot are poor choices for hunting due to the low pellet count. Clay target loads of the same length such as the Remington STS, Federal Gold Medal and Winchester AA loaded with No. 8 1/2 or 9 shot are deadly on woodcock in the timber and quail on preserves.
For everything else, the 3-inch shell loaded with 11⁄16 ounce of shot is the way to go. I use No. 6 shot on pheasant, No. 7 1/2 on grouse, mountain quail, chukar and Huns, and No. 8 for other game I hunt with .410-bore guns. At present, Federal loads No. 8 shot in the 3-inch shell and that company--along with Remington and Winchester--loads it with No. 6 and 7 1/2 shot. I find all to be great performers in the field.
I hunt with the .410 because I enjoy being in the field with some of the trim and lightweight guns chambered for it. Recoil is quite light, and in some heavier guns it's barely noticeable.
Contrary to what some believe, the 3-inch .410 in a gun with an open choke is an excellent choice for a youngster or anyone else who is learning to shoot.
The 3-inch .410 will do at 25 yards what a 20 gauge with 7/8 ounce of shot will do at 35. If you need that extra 10 yards of effective range then by all means choose the 20. On the other hand, if most of the birds you shoot hit the ground no farther away than 25 yards, then you are a candidate for a smooth-swinging, quick-handling shotgun chambered for the 3-inch .410 shotshell.