You could try IMR's Trail boss. It's very low density. You'd have to experiment, but I suspect you could fill the case and still have a tame load.

Biggest risk would be too light a load that didn't clear the barrel.

Another option is H4895. Hogdon says you can drop down to 60% of the max load for a light load. Accuracy may not be good. FWIW...as I have no idea if H4895 is a recommended powder for a 450 Nitro load.

 

Thanks,

I noticed that Hogdon has .45-120 Sharps data under Cowboy Action Long Range Rifle. It lists H4895, Benchmark, H322, H4198 for a 350 grain cast bullet and adds Varget to them for a 405 and 500 grain cast bullet. That .45-120 Sharps case is dimensionally close to .450 Nitro 3 1/4".

I've heard that some have used A-5744 (aka XMP-5744 or AA-5744) for reduced loads.

Hornady tech support told me they have no .450 Nitro 3 1/4" loading data even though they make loaded ammo, cases and bullets. You would think they would have such data. They list loading dies and a shellholder too, but they have not been made as yet. I was recently told 6-8 more weeks by Hornady for loading dies and shellholders.

 

5744 reduced loads in .450 3¼” Nitro Express cartridges


15 Oct 09 email from:

Johan Loubser
Ballistician
Ramshot/Accurate Powders


Caliber: .450 3¼” NE (Nitro Express).
Barrel: 24”
Powder: Accurate -- 5744
Bullet weight: 350 grains
Low load: 46.0grains (1750 – 1850 Ft/p/sec)
Mid Range load: 56.0grains (2050 – 2150 Ft/p/sec)
Bullet weight: 400-405 grains
Low load: 44.0grains (1600 – 1700 Ft/p/sec)
Mid Range load: 53.0grains (1850 – 1950 Ft/p/sec)

NOTES:
It’ important to note that SAFETY is our prime concern therefore we strongly recommend.

1. TO ALWAYS BEGIN LOADING AT THE RECOMMENDED MINIMUM “START” LOAD and develop loads in 2% increments towards the MAXIMUM load.

2. If at all possible, measure the velocity and correlate with our data.

Johan Loubser
Ballistician
Ramshot/Accurate Powders

 

Try 30-06 or 308

 

E-mail Supieror Ammo they are a custom house and , I have bought ammo for the 450 3 1/4" from them, they can help.

All so pop over to accurate reloading forum, in the big bore and african section there are a couple of guys there that can help you, they all so hang out in the double rifle section

Most of the reduced loads require a filler , and they have lots of info to share.

 

Just a quick question.

Double rifles are regulated so that both rifle barrels shoot to the same point of impact at a specific distance. Usually fifty yards for dangerous game rifles. My 450NE is dead on at fifty with either barrel using rounds loaded to the original specs.

Once you start monkeying around with trying to do reduced loads aren't you going to change the point of impact on both barrels?

Assuming you are limiting yourself to short distance shooting, I wouldn't think the reduced loading would be necessary. I mean the 450NE shoots a huge bullet but at low (by today's standards) velocities. Yes, it would make a big hole but probably wouldn't destroy more meat than a 7mag.

 

Sometimes you can come up with a reduced load that is pretty accurate, sometimes not. At ranges up to fifty yards or so, I might be able to come with an acceptable load.

 

Have you considered using black powder and .450 Black Powder Express loads? The external case dimensions are the same but the BPE uses lighter bullets. I can't comment on any regulation difficulties at this time.

 

In this month's SA Hunter magazine there is an article about what a custom rifle really is, why some "custom" rifles are not.

The author posted beautiful photos of his custom built .450 Rigby on a Mauser Magnum action.

 

I've heard that some have used A-5744 (aka XMP-5744 or AA-5744) for reduced loads.

Less expensive is Shooters World Buffalo Rifle. Same powder and what I use for reduced loads in a .416 using less than 400gr solids