The following chrono data is from my stock G20 in about 95 degree weather. Data breakdown is as follows:
Bullet / Powder Weight / Powder Type / OAL / Primer / High Velocity / Low Velocity / Average Velocity
Speer 200 TMJ 14.0g AA#9 1.260†CCI300 1294 1285 1288
Precision 200 FP 10.5g AA#7 1.260†CCI300 1179 1152 1166
Star 180 FMJ-FP 11.5g Blue Dot 1.260†CCI300 1285 1260 1279
Star 180 FMJ-FP 9.5g VV 3N37 1.255†CCI300 1222 1210 1214
Speer 200 TMJ 9.6g Vectan SP2 1.250†CCI300 1179 1117 1144
Hornady 155 XTP 15.9g AA#9 1.260†CCI300 1377 1332 1360
Win 175 STHP 11.5g Blue Dot 1.250†CCI300 1262 1200 1228
Star 180 FMJ-FP 11.0g Blue Dot 1.250†CCI300 1215 1154 1196
Star 180 FMJ-FP 10.5g Blue Dot 1.250†CCI300 1219 1139 1161
Star 180 FMJ-FP 10.0g Blue Dot 1.250†CCI300 1151 1103 1131
Star 180 FMJ-FP 10.8g Blue Dot 1.250†CCI300 1257 1093 1167
Hornady 200 XTP 7.7 Power Pistol 1.260†CCI300 1116 1097 1106
Star 165 FMJ-FP 12.8g AA#7 1.250†CCI300 1339 1291 1314
Star 180 FMJ-FP 9.2g Power Pistol 1.260†CCI300 1297 1271 1285
Sierra 135 JHP 11.5g Blue Dot 1.250†CCI300 1220 1179 1203
Rem 180 GSHP 10.3g 800-X 1.260†CCI350 1317 1225 1260
Hornady 200 XTP 10.5g HS-7 1.265†CCI350 1285 1247 1266
Edited to add the standard disclaimers: use at your own risk, cross check data with loadbook, start low and work up, etc. Use your head