2 Attachment(s)
Lyman M die expander plugs
I've been searching Lyman M die expander plugs.
I have found a few things that might help. I hope I can post my purloined pics.
In the first pic it shows A die cut away that tells how far the case should be pushed up onto the M expander plug. The second pic shows it with more detail.
The second The case at A is expanded to the minor size of the plug, just under bullet diameter. B shows the case pushed just up onto the step. This expands the end of the case to just over the bullet diameter. About 1/16 inch is plenty. Just enough so the bullets sets into the case a bit.
At this point a bullet will just set down into the case. It will set straight in the case.
Now if you seat the bullet it will seat straight. If the end of the case were it is expanded to just over bullet diameter is to large to allow the cartridge to chamber, you can adjust your seating/crimp die to crimp this edge in enough to allow the cartridge to fit the chamber.
On revolver rounds you can adjust the seat crimp to crimp this edge into the crimp groove of the bullet.
You can also push the case up to C, were the end of the case gets a flare. This is for Boolits that are cast to a lager size.
If you want you can get or make your own to better fit larger cast boolits.
I believe these are about the best way to expand for cast boolits.
Some one asked why their 7.62x54 dies came with two expanders. Most of the Russian built rifles had a bore size of about .300x.310 bore and land size, some went a bit bigger than this.
When the Russians fought with Sweden The Swedes captured a lot of the Russian Rifles. The Swedes rebarreled these rifles with a tighter bore, about .300x.308 bore and lands. So most die makers know this and supply two different expanders, one for the smaller bore size and one for the larger.
Leo