I've found only two manuals by different bullet makers, which seem to be the only ones still making bullets for a .405 Win (.411-inch diameter).

I also own a Marlin 45-70. The two manuals (Hornady and Barnes) give several different, progressively hotter loads for the .45-70, depending on what type of rifle you're using. The old trapdoor Springfield gets less powder than the Marlin 1895, which in turn maxes out with less powder than the loads developed for a Ruger No 1. The No. 1 has a stronger action that can withstand greater pressure.

My new .405 Win is a Ruger No. 1. All of the .405 data by Barnes and Hornady were from testing a lever-action, specifically a Winchester 1895, which I don't believe is even as strong as the Marlin.

It seems to me that the stronger Ruger action should be able to withstand greater pressure than a Win 1895. Yet neither bullet-maker has published any enhanced loads for .405 fired in the Ruger No. 1.

Wouldn't it be possible to safely develop enhanced .405 loads to take full advantage of the Ruger's strong action? I am thinking of using the .45-70 variations as a rough guide for how much more powder to add, while of course keeping alert to the usual signs of excessive pressure.

Yes certainly. You can load a #1 until the primers blow. Guys have loaded the 405 #1s to make a 450-400 Nitro out of it; no problem, as you are using 60K psi instead of 40. 400 grain bullets. I might have read that Boddington did that for his wife.
Work up loads like for any other super strong action.
On the Win vs Marlin 95 thing. I think the winchester is stronger. I think. Doesn't matter.

Thanks for the response. As I suspected, but I have sent emails to Barnes and Hornady to ask the question. They probably won't give me any useful info, so I'll probably have to work up the load on my own.

I have no idea whether Marlin or Winchester lever-actions are stronger, really. Wild West Guns told me years ago the Marlin was stronger, but they were selling me the rifle at the time, so who knows?

Barnes nor Hornady won't and can't tell you anything but what is in their book for liability reasons; they limit their pressures so someone won't wreck an old rifle. Just work it up on your own; you can't hurt a #1. As for the 95s; I just look at the receiver side wall thickness, and locking block, which are much bigger on the Winchester. And the barrel shank too. I do know that the Marlin is very strong too; I have built .405s (2.2 inch) on them and loaded them until the levers start to open on their own.

You can probably load up to 2000 to 2100 FPS with the right powder and some careful development in the 405 Ruger no. 1, and you could also cut the throat to be able to seat the bullets out giving you more powder space..Judge G did that with a Win. mod. 95 and got 2000 FPS plus, so in the Ruger no. 1 you could get to 2200 I betcha, just have to work up to the guns max and then back off a grain or two. Not sure what powder I would use as Ive not done that. The Ruger is about the strongest action Ive worked with.

Roland, I just worked up a number of loads for my wildcat .405 Grenadier for use in the Mosin Nagant.

http://forums.accuratereloadin...391073232#7391073232

My wildcat cartridge case holds 73gr of water, the .405 Winchester case holds 78gr.
You should be able to load any of these loads in your Ruger .405 Winchester and still have room to work up.
Work UP, that is, if you don't mind the recoil!