Lyman neck expander buttons

[queen_stick]

I bought a die with a 6.5mm expander. I would like to get different expander buttons for the same die body (6mm, for example). I can't find the buttons anywhere unless I buy the entire die. Do I need to buy an expander die for each caliber? Or, is there a place to get expander buttons that I simply didn't find while looking around on the Internet?

 

[Laurie]

Most makes / models of die don't allow you to change the button. You can usually order a complete decapper stem / expander assembly, so specify one in your desired calibre.

Alternatively, and I think a better alternative, is to go down the mandrel route. Lyman makes 'M' dies in the entire range of calibres. Sinclair provides a mandrel body in 7/8X14 tpi form to fit all normal presses with a range of interchangeable mandrels to fit the body for all calibres from .17 to .338. No doubt, K&M and other firms who make neck-turning tools do the same. You don't say what cartridge you're working with as this may affect choice. In my experience, the Lyman 'M' die body is a bit too long for BR and similar cases while this is not a problem with the Sinclair arrangement as you'd expect since lots of PPC users buy this kit.

These mandrels are designed for neck-turning but work just as well in neck expansion for sizing. They come in two types / diameters for each calibre (related to neck-turning needs). Expander mandrels are 0.001" under bullet diameter, and Turner mandrels are 0.002" under bullet diameter, so most people will choose the latter for use with a resizing die.

One potential problem is that the decapping pin is part of the expander assembly on a normal die, so you either have to reduce the button diameter on your existing assembly below 0.235" or so diameter, or remove the assembly and decap as a separate step using one of the many makes of decapper die on the market. I use the cheap Lee model for cases with 0.081" flash-holes and the more expensive Redding version with the optional small diameter rod and small pin for 0.061" holes on BR and 6.5X47L brass (listed as a .20 calibre stem by Redding).

Neck expansion with a good mandrel such as the Sinclair which has the mandrel itself floating inside the body so it self-centres is superior to most conventional die setups as you push the expander into the neck, while the latter sees you pull the case over a rigidly fixed ball and risk pulling the neck out of alignment. You do still need to lube the inside neck walls though, even though there is much less effort required in the operation.

Laurie,
York, England

 

[queen_stick]

Thanks for the response Laurie.

I haven't had any problems with run-out using my Lyman M die on the 6.5-284 brass, so I think I'll stick with those dies until I find a reason to spend the extra money on the a Sinclair set. I wanted to use the same die body and just put a 6mm button in it to initially size my 6BR brass, rather than buying the entire die. I think you're right though, the die body may be too long for that to work. I'll take a look at it tonight when I get home.

 

[Laurie]

I wasn't knocking the Lyman 'M' die - I've used them for years and have three or four of them in different calibres!

If I were buying a mandrel expander for the first time though, I'd think I'd go down the Sinclair die body + interchangeable mandrels route with what I know now. The floating set-up of the latest version (not earlier models though that use a lock setscrew) is very good.

In any event, as you note, case runout is usually low when good quality brass is sized in a good die and mandrel rather than ball expanded. I think the extra step is well worthwhile.

Laurie