I have several 40-60 Maynard chambered rifles and have made hundreds of cases from 30-40 Krag brass. I am not sure that once you have the 405 cases shortened your neck thickness will not be a problem. Trimming with a hack saw and then and then squaring in your case trimmer may be a little difficult without a trim die but is probably your best choice.

SSS

File trim dies work good, you can buy them from CH4D.  Probably not any need to get a 40 Maynard specific, Long as the neck is the right size you can adjust the length by how far the die screws into your press. Email Dave at CH or send him one case that is correct. He can match up.

I am forming .25 Krag with  3 CH4D file trim dies.  7mm 08 260 Remington 25/08  Caliber makes no difference each sizes the neck down just a bit ending up at proper .25 Krag size. Length only caliber marked on the die is not important long as it's proper neck size.  Bottleneck case dies will be larger than your Maynard case at the base anyway

Finished product probably needs to have the neck turned to chamber.  I use Sinclair's outside hand turner.  You can ream inside but takes more equipment. 

Boats

Big job lot of cutting, down few cases to trim, I chuck up in the lathe indexing the case mouth on a pilot taken from a Redding Case Trimmer.  Set up is laborious if trimming 100 or so

File and trim is quick but you have to buy the file trim dies.

Boats

He has the .405 because he has an original chamber and needs thicker brass. 

I use a lathe with the open end supported on a mandrel to prevent deforming the brass. I always cut long and do a final trim with a Forster case trimmer.

Without a lathe, the tubing cutter idea sounds like the best idea. You will need a mandrel inside the case to cut against. Cut them long and trim to size.

Tube cutter did  not work for me, but never tried 40 Rods trick of bucking up the inside, Also some tube cutters work good others made to sell and won't work at all. I am going to try some scrap brass  now see if I can cut with the cutter

It all depends on what you have and how many you need to do.

Boats

Thick abrasive cut-off wheel on the Dremel to cut the cases slightly long, then into the case trimmer to finish.

Quote:


If you are in need of a tubing cutter, visit your plumbing supply dealer and ask to see their Rigid line, which is American made.  Avoid the temptation to shop at Harbour Freight for this item, because you want to cutting wheel to run true for the best results.

Buy the smallest size that will accept your brass case diameter, you don't need anything larger.  Also, buy a package of replacement cutting wheels (which are changeable), since the brass is a little harder on the cutting edge, whereas the tool is designed for copper which is softer than the brass you will be cutting.  Also, once the cut is made, the cutting wheel edge will be onto the underlying mandrel.  My experience.

C.M.M.