I'm in the process of building a rifle chambered for the .40 Newton.

Reloading data are very hard to find, but I got a load with a 300 grs bullet and 69 grs of Dupont #10 powder, 3042 fps.

I have tried to research Dupont #10 powder to find a modern equal, but there is nothing to find.

Does anyone have any knowledge of this powder?

That was a long, long time ago. Jack O'Connor used to throw those terms around since he was there, in WW I ROTC, reloading with those powders. I believe he said MR (Military Rifle) #15 became 3031 and MR 17 1/2 became 4064 in the 1930s. And I think he said 3031 came out in 1931. IMR is "improved Military Rifle." "SR" was "sporting rifle." Sometimes "Cartridges of the World" has references and comparisons. Hodgdon Powder Company has about the broadest base of info on modern powders, but this would seem to be at the very, very beginning if at all. I believe Newton "went broke" in the 1920s before the Depression. The LEE reloading manual lists cases by capacity in cc's. It would not be rocket science to fill a case with water and figure out the "cc's" and interpret from there.Luck.

IIRC it was around IMR4895 in burn rate.

When I got my first 256 Newton,(20+ yrs ago) I remember the Old Man I bought it from gave me load data of 129gr and 45 gr Dupont No 10.
He told me to use IMR4895 in its place.


He told me George Nonte used 50gr of No. 10 with the 160's but the Old Man said it was too hot, he said it was OK with 140's.

Never saw a burn rate table with it and ended up developing a load with IMR4350.

This may not help you too much with the .40 project , but its all I know.

Thanks for the answers guys.

I know the Dupont #10 is old stuff, I heard they stopped making it around 1915.

But since this was the only load I have got, I was nice to get some info.

I think the easiest would be to start with .416 Taylor loads and see how it goes.

Edit.

I had a friend round check some loads in a ballistic program, which has the .400 Niedner listed. It is practically the same as the .40 Newton. It shows that the Vihtavouri N 135 would be the best powder to use for the bullets I plan to use, 300 grs, 360 grs, 400 grs.

It sounds like a very interesting round .. When you get it running please post your results on the Bib Bore Forum .. Someone should be able to do a Quick Load on it .

I have had some computer problems and can't find the electronic copy of my .400-Niedner article that I wrote for PS. The .400-Niedner is the same as the .400-Newton reintroduced in 1939 by Niedner. If you don't have any of the older books listing reloading info for this round let me know and I will try to post some. I remember stopping when I got a 300gr bullet to 2700fps. I have some new brass (375-Ruger) but have not had the time to form new cases.

The rifle,

Michael,

Thanks. I don't have any of the books mentioned above, so if you could post some reloading data that would be appreciated.

Also your article for PS would be interesting. If you can't find it on your computer, do you now if PS sell back issues?

Your Niedner rifle looks very good, how long is the barrel?

The .40 or .400 Newton is basically the same as the .400 Niedner, as well as the .400 Gipson. A genuine American big bore.

I also plan to use .375 Ruger brass when I have the rifle finished.

Here is a picture showing the different cases, from left to right:

.416 Newton, made from .375 Ruger
.40 Newton, made from .375 Ruger
.400 Niedner, made from .35 Western
.400 Gipson, made from .30 Western

And to compare:

11,2x72 Schuler, said to be the parentcase for the big Newtons.
10,75x68.

I cannot find the article here, it was published in November of 2000 in PS and yes they have back issues although I have no idea if this one is available.
Gibson was working at Niedner’s in 1940 and I suspect he was the one who developed many of their cartridges that used the Newton case.
For my own use I used 458 H&H cases that I ran into the die and fire formed the brass in front of the belt. I have some 35 Newton brass but it's old and I don’t trust it. Do you have an expander die for the Ruger brass? I’ve not taken the time yet to make one.
The 1939 Niedner add said they got 2700FPS with a 300grain bullet so I loaded it up with 3031 until I got 2700 and stopped. If you use 3031 I suggest that you start around 64gr and work your way up. My notes show I got 2745fps using 70.3grs of 3031. In my .400 Whelen I found that I could get an extra 100fps using North-Fork bullets and I suspect that this same load with NF would be close to 2800fps.

Thanks for the reloading data.

I don't have any dies yet, will custom order some when I have fireformed some cases.

Yes, the .35 Newton brass may crack, but then again it may hold together. If you have many cases, and some to spare, please let me know. I could use some for fireforming cases for the dies.

I plan to use the North Fork 300 grs and 360 grs, have you tried them in your Niedner? Also Woodleigh have some 400 grs that would be interesting to try.

I will contact PS and hear if they got a back issue with your article.

Getting a 300 to 3000 with less than 70 grains of powder should be the new model of efficiency! Or insano pressures!

Well, if you read Richard Simmons "Wildcat Cartridges" from 1947, there are some data.

Both the .40 Newton and .400 Niedner, gives 3000 fps with a 300 grs bullet. It is mentioned that the .400 Niedner were fired in a 28-inch barrel. The .400 Gipson gives a velocity of about 2700 fps, 68 grs #3031 and 300 grs bullet.

Although the pressures may have been high, I don't think they were over the limit. Besides, these guys knew what they were doing, and the Newton case is a very efficient case design.

quote:

I plan to use the North Fork 300 grs and 360 grs, have you tried them in your Niedner? Also Woodleigh have some 400 grs that would be interesting to try.

I have some heavier .411 bullets that I want to try in both my .400-Whelen and .400-Niedner but just have not had the time. On my to-do list is to try lead bullets in both.