I've got a Lee expander die that I leave set up for 38Spcl...I haven't had any problems with it so far. I have a full Hornady set that I leave the expander set up for .357. The Lee expander was part of an incomplete set that I picked up at a gunshow so I didn't have to readjust the expander every time I switched from 38Spcl to 357 or vice versa.

What brand press do you have? If the top plate (where the die mounts) is very thick then it might be possible that you can't thread that Lee die close enough to set it for .38Spcl cases.
I use mine in an old C-H 3-station "H" press...but I have used it before on my RCBS Reloader Special without problems too.

It is possible that you've got a bum die too though.

 

This should not be a problem, the shell holder touches the expander die mouth. I think what they did was send a 357 expander plug with a 38 die. I could put in some washers but I got ahold of Lee and they are sending a 38 plug to replace it. Hope this works

 

This should not be a problem, the shell holder touches the expander die mouth. I think what they did was send a 357 expander plug with a 38 die. I could put in some washers but I got ahold of Lee and they are sending a 38 plug to replace it. Hope this works

Yeah, if the die is threaded in all the way so that the shellholder is touching it then you've got a problem die....or more specifically the expander insert that they're sending you a replacement for.

Glad to hear that Lee is working to "make it right" with ya...I've never had a problem with customer service from them in the past.

 

Do you have the little metal funnel supplied with the die or a powder measure screwed into the top of the die? I think it needs that to prevent the case from just pushing the expander up and offering no resistance.

 

I received the new expander insert. It was about 1/4 inch longer than the one in it.

 

they probably got it mixed up at the factory with one for a 9mm die, pull the one from the 9mm die you have its probable that they will be the same size...