Finding the Trail Boss loads in the .450-400 3-inch NE

[Abert Rim]

Well, I cast up a batch of bullets using my new Accurate 41-350W mold. They weigh 364 grains lubed, gas-checked and sized to .410 using my range scrap alloy.
Going by the IMR formula for finding Trail Boss loads, I marked the neck of a Hornady case at the point where the seated bullet's base ends, filled the case to that mark with Trail Boss and weighed the charge -- 33 grains. Using 33 grains as the maximum load, the minimum load is calculated by multiplying it by 70 percent, which yields 23.1 grains as the starting load. The rifle arrives tomorrow or Monday, so it will be next week before I can test the loads. Fun stuff, though. Overall length of the loaded cartridge is 3.682 inches.

[j p sixguns welldone]

I'm looking forward to hear of your result's. i've had trouble finding brass. keep us posted does accurate make a heavier mold gas checked never used one of their molds

[Abert Rim]

JP, Tom at Accurate has an amazing catalog, and he will also cut a mold to your specs. I love his stuff.
https://www.accuratemolds.com/catalog.php?page=1

P.S. I would be using 5744 instead of Trail Boss if I could find some.

[elk hunter]

Which rifle? Double, single, make? Pictures Please.

I always wanted a 450-400. Very versatile caliber. Big enough for buffalo, small enough for plains game.

[Jedman]

I have played with TB powder quite a bit in some of my very large calibers and was only after accuracy. What I found was the best accuracy always was just short of a full case full ? Usually with the level of powder between 1/4” to near 1/2” below the bottom of the bullet when seated to the length you decide to use.
Probably about what you stated in your post but it has proven time and time again to me that somewhere in that range produced the best accuracy.
A friend of mine tried TB in a 45-120 rifle and found out by working up a grain at a time and taking chronograph readings that a full case full where the bullet touched the powder charge we’re actually slower in velocity than several grains less ? Sounds strange but it was true in that case.

Jedman

[ATCDoktor]

A friend of mine tried TB in a 45-120 rifle and found out by working up a grain at a time and taking chronograph readings that a full case full where the bullet touched the powder charge we’re actually slower in velocity than several grains less ? Sounds strange but it was true in that case.

I found the exact same thing was true in my experiments with Trail Boss in the 45/70.

I got to a point in load development that the more Trail Boss I added the velocity went down but signs of pressure went up.

[Abert Rim]

Elk Hunter: The .450-400 I am loading for is a Ruger No. 1 Tropical.
Jedman, I loaded a few with 30 grains of TB and a few with 31 for starters.

[15meter]

Some light reading here:

https://castboolits.gunloads.com/sho...-Nitro-Express

I'll have to check, but I think I've made cases from 9.3x74R and 400/360 Purdey cases. Geezer memory.

If I remember correctly, the Purdey cases have a thinner rim and worked better in the double rifle that I was loading for. The 9.3 with the thicker rims would almost, but not quite close and lock completely.

[15meter]

And just to tie the threads together:

https://castboolits.gunloads.com/sho...-Nitro-Express

Easier for the next guy going down the rabbit hole of old weird calibers

[Abert Rim]

Wow. I had forgotten that 11-year-old thread. Thanks.

[15meter]

Some light reading here:

https://castboolits.gunloads.com/sho...-Nitro-Express

I'll have to check, but I think I've made cases from 9.3x74R and 400/360 Purdey cases. Geezer memory.

If I remember correctly, the Purdey cases have a thinner rim and worked better in the double rifle that I was loading for. The 9.3 with the thicker rims would almost, but not quite close and lock completely.

And I mis-remembered.

The 9.3x74R were used to make 400/350's that were fired in a Mauser rifle. the 400/360 Purdey's were used to make 350 Rigby #2's for a Rigby double, the thinner rim allowed the double to fully lock up.

Geezer memory.