I'm not into the straightwall cartridges and don't have any experience with them. However, I do enjoy tinkering with ballistics, so I ran the 350 out on a Ballistic Calculator and copied the 20 gauge info from a Hornady advertisement. Both guns are zeroed at 150 yards.
As you can see below, the energy in ft/lbs at the muzzle is about the same, which means that recoil should be about the same with all other factors being equal. However, at 200 yards the 350 is giving you 13% more energy and also has 3 inches less drop.
My thought are that you should be able to get a good 350 to group much tighter than a 20 gauge at 200 yards, but as stated earlier - I don't have any actual experience with one. I hope this helps.
20 gauge with Hornady SST 250 slug:
Muzzle vel = 1800 fps Drop = -1.5 inches energy = 1798 ft/lb
50 Yards vel = 1628 fps Drop = +2.5 inches energy = 1471 ft/lb
100 yards vel = 1470 fps Drop = +3.3 inches energy = 1200 ft/lb
150 yards vel = 1331 fps Drop = 0 energy = 983 ft/lb
200 yards vel = 1212 fps Drop = - 8.2 inches energy = 815 ft/lb
350 Legend with 180 grain Soft Point Factory ammo
Range (yd) | Drop (in) | Wind Drift (in) | Velocity (fps) | Energy (ft-lb) |
---|
Muzzle | -1.5 | 0.0 | 2100 | 1762 |
50 | 1.5 | 0.4 | 1942 | 1508 |
100 | 2.1 | 2.0 | 1793 | 1284 |
150 | 0.0 | 4.9 | 1652 | 1091 |
200 | -5.2 | 8.9 | 1520 | 924 |
PS - This is where I got the slug info:
https://www.hornady.com/ammunition/shotgun/20-ga-sst-slug-250-gr-sst#!/