.378 to .338

Discussion in 'Reloading' started by Speedo, Nov 3, 2011.

  1. Speedo

    Speedo Well-Known Member

    Oct 3, 2010
    Can I use .378 Weatherby brass to make .338-.378 brass without too much trouble? I've found a bunch of new .378 brass for about 1/2 the price of new .338-.378 brass.

  2. 4xforfun

    4xforfun Well-Known Member

    Oct 1, 2007
    I would sure think so. You might need to take the brass down to .338 in steps....maybe not. But, that is a pretty big squeeze. I am not sure about the neck thickness....depends on your chamber dimentions.

    I baught a whole bunch of 340 wby casses for my 300 wby comp guns.....I have a .334 neck, so I neck turn no matter what, but a stock chamber....just size and shoot.

    Now , on the technical side......you really don't need to worry about headspace issues, as the loads will headspace on the belt. BUT...I only reduce the neck size far enough down the neck to get a tight fit when closing the bolt...almost a crush fit...kind of like a faulse sholder when forming Dasher brass. I also do this when I reduce 6.5-47l brass to 6mm.....I only size to 6mm far enough down the neck so the bolt closes stiff.
  3. cowboywhorses

    cowboywhorses Well-Known Member

    Mar 14, 2010
    Just did some full length 375 Chevy -tac to 338 . This is for a 338 snipe-tac, now I reduce load then fire form the case.

    I was lucky my full length die was made help keep the neck tenison about 3-4 thousands snuggger.

    One thought you may have to go a bit smaller then expand back.

    Also to help with case life you may need think about annealing.

    Food for thought