Have to use a more open choke though.
Maybe, maybe not. Just choke for the distance of your shots. Here are a few of my pattern numbers to give you an idea of the kind of performance you might get from 1-ounce steel target and small game loads.
Pattern results from a 12-gauge Browning Citori with 28" Invector-plus barrels using Briley flush chokes (patterns average of five, 30" post-shot scribed circle, yardage taped muzzle to target, and in-shell pellet count average of five).
12 GA 2 3/4" WINCHESTER XPERT GAME & TARGET STEEL LOAD
1 oz #7 steel (437 pellets) @ 1325 fps
30 YARDS
Xpert Steel 2 3/4" 1 oz #7 steel (437 pellets) – CYL / 231 (53%)
Xpert Steel 2 3/4" 1 oz #7 steel (437 pellets) – SK / 319 (73%)
Xpert Steel 2 3/4" 1 oz #7 steel (437 pellets) – IC / 363 (83%)
40 YARDS
Xpert Steel 2 3/4" 1 oz #7 steel (437 pellets) – LM / 278 (64%)
Xpert Steel 2 3/4" 1 oz #7 steel (437 pellets) – M / 286 (65%)
Xpert Steel 2 3/4" 1 oz #7 steel (437 pellets) – IM / 300 (69%)
Xpert Steel 2 3/4" 1 oz #7 steel (437 pellets) – LF / 306 (70%)
Xpert Steel 2 3/4" 1 oz #7 steel (437 pellets) – F / 299 (68%)
12 GA 2 3/4" WINCHESTER XPERT GAME & TARGET STEEL LOAD
1 oz #6 steel (306 pellets) @ 1325 fps
30 YARDS
Xpert Steel 2 3/4" 1 oz #6 steel (306 pellets) – CYL / 184 (60%)
Xpert Steel 2 3/4" 1 oz #6 steel (306 pellets) – SK / 234 (76%)
Xpert Steel 2 3/4" 1 oz #6 steel (306 pellets) – IC / 261 (85%)
40 YARDS
Xpert Steel 2 3/4" 1 oz #6 steel (306 pellets) – LM / 220 (72%)
Xpert Steel 2 3/4" 1 oz #6 steel (306 pellets) – M / 222 (73%)
Xpert Steel 2 3/4" 1 oz #6 steel (306 pellets) – IM / 227 (74%)
Xpert Steel 2 3/4" 1 oz #6 steel (306 pellets) – LF / 229 (75%)
Xpert Steel 2 3/4" 1 oz #6 steel (306 pellets) – F / 234 (76%)
50 YARDS
Xpert Steel 2 3/4" 1 oz #6 steel (306 pellets) – F / 162 (53%)
Good luck!