Home Forums Hunting & Shooting Gunsmithing .218 bee and .22 hornet

Curious question from a non-gunsmith...
My initial thought was ... if the .22 hornet is based on the .25-20 case and the .218 Bee is based on the .32-20 case (which the 25-20 and 32-20 should have the same dimensions at the rim), why couldn't any .22 Hornet be rechambered to .218 Bee?
Then I looked at Saami.org for case dimensions and the rim diameters are different for the .22 Hornet and .218 Bee.. .why is that if they are based on basically the same case? Also, what other factors are there in determining if a .22 Hornet could become a .218 Bee (I'm thinking specifically of a Ruger 77/22 Hornet or CZ 527).
Thanks for the help,
kstockfo

I believe the Swift is the 6mm Lee Navy. Swift has a .473 rim diameter and I believe the bees diameter is .408

Not even close in dimensions...

You are correct that the 218 is based on the 32-20/25-20 case. The Hornet started life as a black powder round, 22 WCF. Black powder and 22's don't work well so the rim thickness was increased to prevent use in older rifles, and the resulting smokeless round was named Hornet. It doesn't have any parent case as such.
It would take a lot of work to convert a Ruger or CZ to 218. If you want more performance, the K Hornet is your best bet.

Not sure where you got your information but the 22 Hornet was not derived from the 25-20 Winchester. Nor even the obscure and obsolete 25-20 single shot. The Hornet is supposedly derived from the old Winchester 22 Centerfire, a blackpowder round. That's open to debate depending on whom you source.

The 218 Bee is the 25-20 necked down to .224. And the 25-20 is the 32-20 necked down to .257. All the same parent case. As Shrapnel demonstrated, there's considerable difference in dimensions between the Hornet and Bee.

.22WCF and Hornet rims are the same thickness. I have several old examples in my collection, and in fact the .22WCF rims are a couple thousandths thicker than the modern Hornet rims. I've used Hornet brass to load .22WCF's in the past with no issues. (Really the only difference is that .22WCF uses a larger diameter bullet.)