Looks real similar to an Ideal/Lyman 310, but I'm pretty sure it isn't one.
Tools like that are called "tong" or "nutcracker" loading tools. One of the earliest mass produced versions was the Ideal 310 mentioned above. But there were who knows how many one-offs and small runs by individual gunsmiths and small manufacturers. And, like I said, what you have there doesn't look like a 310.
Sorry I'm not more help...
- DAA
