Birdshot for small game is pretty poor in my opinion. The pattern spreads so quickly and gets thin. the donut shaped patern is a fact of life with all rifled bores shooting shot.
I like light loads with round balls or light cast bullets for rifles for small game or grouse shooting. Keeping he velocity around 1300 fps or less keeps the noise down, and also themeat destruction. Just shoot them enough to know where they hit compared to your regular load. They usually hit about 2" low for me. I've loaded light loads for 30-30, 30-06, 338, 44, and 45-70. When the loads are kept light, the noise is about like a 22 LR load or a little more. Give you about 40 yards of usable range.
I like light loads with round balls or light cast bullets for rifles for small game or grouse shooting. Keeping he velocity around 1300 fps or less keeps the noise down, and also themeat destruction. Just shoot them enough to know where they hit compared to your regular load. They usually hit about 2" low for me. I've loaded light loads for 30-30, 30-06, 338, 44, and 45-70. When the loads are kept light, the noise is about like a 22 LR load or a little more. Give you about 40 yards of usable range.