The Saeco 571 (300gr, tapered) runs .3830"-.3835" on the base band.
The slightly shorter Saeco 738 (250 gr, tapered) runs .3810"-.3820" on the base band.
I have a rifle with a .382 groove diameter. Other than the SAECOs, I haven't found any other off-the-shelf molds that will throw a bullet this large.
One of my favorite loads in the rifle is Lyman 375449 (.377 as cast in ACWW) paper patched up to .382 (no gas check) over IMR3031.
-ktw