I have four H&R 243s, two Superlights and two Ultras, the older Ultra shoots 100gr Federal Powershoks and 95gr Fusions into well under 1" at 100yds, the other Ultra liked 80gr Rems, it got rechambered to 6mmRem AI tho and still shoots 87gr Vmax handloads excellent. If you get any of the 20" Superlight models, keep the barrel cool and they'll do just fine, but they heat up fast, without bedding the forend it will likely string any shots after a couple, but the first two should be tight, mine like 100gr Speer handloads. The standard contour and bull barrel aren't so sensitive to heat.
Tim