After trying to chamber a new, full length resized HDS 450/400 (3") case in my new (unfired, except presumably at the factory) Ruger No. 1, I find that the rim thickness, 0.058 inch, does not allow me to close the action.

So, I'm wondering whether the rim recess in my chamber was mistakenly cut too shallow, or whether the rim thickness of my case is excessive (the cartridge diagram that I have lists an allowable rim thickness of 0.065 inch).

If someone who has some Hornady factory loads for the 450/400, that work in your rifle, could measure the rim thickness of the cases and let me know what you get, I would sure appreciate it.

I have only one Hornady 450/400 case. It is a dummy round Hornady gave me.

The rim measures .615, mostly except for one place that measures .62.

Are you sure the case is full length resized "enough"?

I've got one of those, 450/400 NE 3" Ruger No.1, being such a Ruger lover and collector, but I have not acquired any brass, dies nor loaded ammo for it yet, being so pre-occupied as I am with the 400/.395 NE.

This will be interesting to see what plays out over this.

Ruger boo-boo on headspacing the rim recess? Unlikely.

What reloading dies do you have to FL-size the brass?

If there is no mismatch between the chamber reamer and the reloading dies, it would seem rim thickness is the problem.

You could get go and no-go guages to test.
You could sacrifice a case and face it down to see if a thinner rim will close the action.

From the HDS diameter and the max spec allowed there should be no problem ... unless it is a reloading-die/chamber reamer screwup in compatibility.

Lots of folks have been using the Hornady ammo in that rifle on TV anyway, such as Craig Boddington and his daughter, and Ruger employees on safari.

I'll be getting Hornady brass and reloading dies.

I had no problems with the Hornady factory load in my Ruger #1, but with Bertram brass & reloads, I had to make REAL sure that I'd full-length resized the brass, else the action was hard to close (& on a few just wouldn't close until I pulled the bullets & ran them through the re-sizing die again). It's been my experience that proper re-sizing is critical with the 450/.400 Ruger #1.

Yep,
Sounds like a brass sizing issue. Whew! had me worried for a bit there.

So, what is the secret password to get brass, dies, or loaded ammo from Hornady for the 450/400NE3"?

Sumbuddy who know?

I haven't tried calling them direct, yet. Will do tomorrow and see how squirrley it gets.

Cosmic Squirrel Top Secret password?

I called Hornady today.
The pleasant young lady handling orders said the 450/400 "Jeffery" NE 3" loaded ammo may be shipped out by the end of this month.

No dies or brass for reloading are available yet, unless you know the Cosmic-Squirrel-Top-Secret password.

She wouldn't tell me either, just
"Coming soon."