I have slugged a lot of guns with a hard wooden dowel. We are not talking about POUNDING on the dowel but tapping. I use an unsized cast boolit and oil the barrel with gun oil generously and start the slug nose first with a small plastic mallet. With the rifle held securely and the base tapped in almost flush with the muzzle, I take a piece of dowel about 5" long to get the base of the slug started and when 4 inches is in the bore, switch to about a 12" piece the go to a 16" piece and so on until the slug comes out the chamber end. The idea is to not have a lot of unsupported dowel outside the barrel. Another person really helps to steady the gun or put it in a padded vise. A 3/8" wooden dowel is .375 and a 7/16" is .438 and if they are made correctly, they wont cost you a lot to buy several. I have heard all the horror stories about wooden dowels splitting but in many years of doing this I have never split one and I only use oak dowels. Just remember to take the short piece of dowel out and replace it with the longer pieces and never try to drive the shorter one with the longer. In your Marlin, if it has the Ballard, or non-microgroove rifling, I am betting that the .459 sizer is going to work for powder coating and Track of the Wolf does ship to NZ.Attachment 290611 Here is a 3/8" oak dowel with a .40 S&W case on the end that fits in the barrel of my Marlin 45/70 just right.