There was a time when Lyman offered them in almost every caliber but over the years they kept discontinuing various calibers until today, when I can't even find them on their website. Ebay prices are insane and they're seldom seen in the EE, although I see there's a set in .30-06 available right now.
With the demise of The 310 Shop anyone wanting these tools will find slim pickings in Canada.
I like and use these tools for a couple rifle calibers even though I have a press and standard dies. They're just fun.
There's lots of information out there for anyone interested in their history and use and it's well worth taking the time to do some research for those that enjoy the old tools.
An old thread I posted about the 310:
https://www.canadiangunnutz.com/for...t-of-history-The-Lyman-310?highlight=310+tool
Edit to add: it appears that many of the links in that thread no longer work. How quickly things disappear!