I'm a new member looking for information regarding a rifle that i have pruchased recently thinking it was a 340 Wtby, but actually is a rifle build by J. Shannon of Spanaway Wa. in a 340 Shannon wildcat on an enfield action. Any info regarding reloading of this cartridge would be appreciated. The dies came with the rifle but no information at all.

Thank You in advance.
D. Piper

Welcome to the forum rpiper. Rules are simple, be nice and join in.

What case is the 340 Shannon derived from if you know. I couldn't find any reference to it on my net search. At the worst you might have to make a chamber cast or cast of the dies to find out what case it's based on. If you got any loaded rounds you could mike them and compare them to other cartridges. Have you tried contacting Mr. Shannon?

Bob, thank you for reply. The case is based on the original 340 Wtby Mag. When fireformed
it changes the shoulder to a sharper shoulder, ie almost the same as PO Ackley wildcat
case. I googled J Shannon Spanaway Wa and other searches to no avail. Also contacted
a hunting buddy that lives in Post Falls Idaho to see if he could find out anything pretaining
to J Shannon. I'm assuming this rifle was probably made sometime in the 60's or 70's.
Not sure of that, just assuming as i have owned it for approx 15 - 18 years, just got
interested in shooting it over the last couple of weeks, sort of stupid on my part.

Sounds like you've got an 8mm Remington necked up to .338