I have an interesting custom rifle built by a gunsmith from WA by the name of Shannon. Apparently he was an Ackley fan because he came up with a series of cartridges that he named. One of them was apparently the basis for the 26 Nosler. The 220 is a shortened, sharper-shouldered Swift. CH4D does not have the dies nor the dimensions. So either one would be helpful. It's possible it could be reloaded with some combination of existing dies but first step is to determine what we have here. I suppose I could do a chamber cast or fireform something if it comes to that.

WOW have not heard of that gunmakers name in a LONG TIME.

Can not help you in those dies.
I do have a set of 220 Rocket dies, not sure how close they are.

Yes he made up the 263 Sabre cartridge

J Wisner

Apparently he was a wiz with Enfields but the rifle I have is a Springfield. Enfield, Springfield, what's with all the fields?

I hear Shannon liked to jerk Weatherby's chain a bit, some of his ctgs were improved version of Weatherby ctgs!

Both 220s were based on the Swift. The Rocket is an improved Swift and is longer than the Shannon but the shoulder angle may be the same. Wby hadn't invented the radiused shoulder/neck when he came up with the Rocket.

It's possible Shannon dies may work on a Rocket but I don't see how it could work the other way around.

FYI, I hate to say it Roy Weatherby DID NOT invent the double radius shoulder

That was brought out in 1895 by Winchester in the 25-35 cartridge.

I will pull apart the 220 rocket dies and see if I can measure the length of the shoulder
J Wisner

Taking a closer look the Shannon is the same ctg length as the Swift but with a sharper shoulder .. so it could be same as the Rocket. But for other reasons, I no longer need the dies.