If it helps anyone I've shot the NOE 247 Whisper in a .30-30, it just happened to be a Savage 219 so feeding wasn't an issue. It fit like a glove and was minute of cowpie-on-the-berm accurate at 100 yards offhand with buck'n'bead sights. 24", 1-in-12 barrel stabilized them just peachy, and stoked with 7 grains of Unique shot to the same 100-yard elevation setting as 170-grain cast at full-tilt loadings. Pretty quiet, too. No, they won't feed in a Marlin 336 and if you have to eject a live one you have to pop it loose from the extractor with a pocket screwdriver and shake it out of the ejection port base first.