Yes - Tinker, single stack. I've seen a similar change to single stack, only with delrin slabs in a .45/90 conversion.

I must try that in my 2 groove #4 in .312 Express (new barrel). I re-chambered it with a .300 Win Mag reamer and set it up for the short, 2", .350 Rem Mag case. Using Re#19 (or 22?) 2,940fps with 174's. I do have some hopefully harder, 180gr. Norma steel jacketed BT's to try as well.