I'm PO'ed at Lyman too! Following is a copy of a letter I recently sent them to which i have never recieved a reply. Go RCBS!
I recently got into casting my own bullets for my 38-55 Winchester. I have always purchased RCBS or Hornady products for my other reloading needs. However, as Lyman has long been known as the "experts" when it comes to cast bullets, I purchased a mould and set of dies from Lyman for my 38-55.
The mould works beautifully! It drops perfect bullets everytime. With #2 alloy, they drop out of the mould at a diameter of .379. I then size them down to .378 and lube them with Lyman Orange Magic.
Everything works as advertised up to this point. Unfortunately, this is where I throw your dies into the trash or onto the pile of things that don't work right.
You see, your famous "M" die expands the case to .374 and the step, the heart of this unique die, which is supposed to provide a nice entry for the soft lead bullets only measures .377-.378. That diameter is not sufficient (even assuming the brass doesn't spring back some - which it does) to easily seat bullets measuring .379 as in your 48th manual, or .378 as I'm attempting to use. It works great for jacketed bullets, but that isn't what I bought these dies for. They are advertised as the best thing since sliced bread for cast bullets. However, they don't work at all as they should with cast bullets.
I called about this problem and was merely told to use the next shoulder up on the die which measures .402. That is a big jump and tends to split cases and/or dramatically shorten their lives - which defeats the purpose of reloading.
Since I can get no real help from you folks, my only alternative is to take the expander plug to a machine shop and have it corrected to the diameter it should have left your factory with. I believe I shouldn't have to spend additional money to make a product work as it is advertised to do. Consequently, I will never buy another Lyman product and will probably just go get a set of RCBS dies for this rifle. I gave Lyman a try and unfortunately have been very disapointed