nitro optimised cast bullet cartridge

[wildfire084]

good evening Cast Boolitians! this is my first post so i would like to say hi and thank you for all the cast insights and many hours of fun filled trawling.


This is something that i have been wondering about for sometime and depending on the answer may be the start of a wonderful project.
I am about to buy a 577-450 MH which would be used with nitro and blackpowder loads. this got me thinking that there is an aweful lot of space in that large cartridge for such a small amount of nitro powder.
the proposal: i would like to build a rifle that is optimised for shooting 400-500gr .458 cal cast projectiles at 1200-1500ft/sec and would like a case that would give me 100% load density for 500g at 1500ft/sec using a fast pistol type powder like AP50n or red dot, etc. i would be guess that would be something around 20gr of powder capacity.

My first thought was something like a 45-70 cut down to about 1" (given that i would need to test capasity of that case but use your imagination) allowing me to buy off the shelf dies and just cut them down to keep costs to a min, readily available brass, and last but certainly not least off the shelf.458-459 cast and jacketed bullets.

Please give me your thoughts on this? whether it has been tried before or if indeed there is another cast lead optimised wildcat out that i could use as a test case. depending on your answer the 450 nitro 1 inch may come into exsistance!

Thank you once again and good health
Wildfire084

[dubber123]

I'm not sure you will be able to get a 500 grain boolit to 1,500 fps. using Red Dot at a safe pressure. A slower propellant will get you there, and a 100% density charge will be easy to do with a full length 45-70, which makes for a boring project.... What action will you be using, and what PSI/CUP is it rated to?

[wildfire084]

it will be a large frame martini i think but that may change depending on what is available. i do have a m17 with a boltface machined for .308 norma mag. and 1500 was on the very optomistic side of it but it was to give a good guideline of what kind of performance i would like to achieve but as always i would rather go with slightly less pressure and be safe.

basically i want to minaturize case big bore cartridges. what an odd thought!

[BerdanIII]

What about a shortened (1.5", 2"?) .458 Win. Magnum case? That's already been done and there should be some load data out there; I'll poke around if you want. You'd have to use the Model (Pattern?) 17 action, though. I believe that a CBA member built a Ruger No. 1 chambered for the .50 S&W, but pistol cartridges may not be an option where you are.

[Doc Highwall]

My question is what are you going to use this rifle for?

[wildfire084]

A win mag case might be the idea and i would love to see some load data. Admittedly 1inch was a really long shot as I don’t think I would be able to seat such a large bullet and still get powder in there? The real idea for it in the beginning was something of an engineering problem. I kind of looked at it is as taking away the opportunity for wastage (eg Dacron fillers, etc) whilst making a cartridge that could be a very effective cartridge for both target and some medium sized furry things that would delicious (400g at 1200ft = 1270ftpd..).

a pistol case had occurred to me but i had never seen one throwing such a large bullet but suggestions would be welcome as most are readily available in aus though dies might be the hard part and i already have some very hard to load for cartridges (297-230 morris short...)

Good suggestion on the ruger no 1. Some already come with a 458 barrel.

[82nd airborne]

the .458 case mentioned above is called the .458x2 american (a .458 cut down to two inches) it was developed as a subsonic gun in the vietnam era to the best of my understanding. if you google the cartridge name you will find some data. an interesting round in my opinion

[wildfire084]

458x2" is almost what i want but it still is somewhat overpowder as its overal capacity is still some 60gr of powder. its more a belted 45-70 according to most sites. perhaps taking another 1/2 inch off would make it perfect. that would make modification of dies easy and i have a couple of hundred norma cases laying around. very interesting little cartridge though and something that definitely intrigues me.

[wildfire084]

sorry to throw in so many replies to my own question but thanks to all your help i did manage to find a 1.5 inch version
barnes 458x1.5''
http://www.reloadbench.com/cartridges/w458x15barnes.html
it has the add bonus of being able to use 45 colt and other pistol dies to form with only the need to cut down the brass.

energy is a little on the high side but you do need a little bit of leeway when trying something new.

please keep the sugguestions coming you have been a great help to my obsessive nature! :bigsmyl2:

[wildfire084]

http://www.reloadbench.com/cartridges/w45silh.html

the 45 Silhouette! I'm not mad! :killingpc

[Piedmont]

Why not just use an existing case, the .45-60. You can just shorten .45-70 brass and use a fast twist if you must use heavy bullets.

You can get the performance you want with a standard .45-70 case. For instance, a casefull of 4831 and a 500 gr. cast bullet should be somewhere in the 1200-1300 fps. range.

I would stay away from a casefull of Red Dot in just about any cartridge.

It sounds like you want something like a .454 Casull in a rifle.

[longbow]

Ross Seyfried had a .500 Linebaugh revolver made up and a rifle both of which shot 600 gr. bullets if memory serves and it seems to me he got .50 x 140 Sharps performance from the handgun. I have the article buried somewhere.

He then made up a .475 Linebaugh which seemed to be better proportioned for bullet weight to powder capacity.

There are also the .45 and .50 cal Whisper cartridges.

Any one of those would be interesting.

Longbow

[Doc_Stihl]

What's the reasoning behind requireing 100% load density?

[45 2.1]

There are lathe turned reduced capacity cases available for many of the old large BP rounds to do as you said. There are several adapter cartridges as well. The most interesting would seem to be the use of a 45 Colt in a steel 577-450 MH case.

[wildfire084]

the .475 Linebaugh seems to be right on the money with power and cacity.
the reasons behind not wanting a huge air space is accuacy for the most part as with more cartridges you tend to get the best accuacy with a given powder approaching 100% filled case at close to max pressure. also if you are to fill a case with say powder and dacron or some other filler you get weight variation (now i know this may be splitting hairs with a 500 gr projectile but thats the sort of shooting sports i have been involved with). also miss fire can be an issue.

Wildfire084

[BerdanIII]

From: .458x2" American, M. Ruggiero, The Cast Bullet, #105, Sept. - Oct. 1993

"To date I've used only three cast bullets: the RCBS 350 gr. GC, the SAECO 350 gr. GC and a 405 gr. PB by Lyman. Both the SAECO and the RCBS have been excellent performers, up to a velocity of 1860 fps, using H 4198, IMR 3031 and Hercules RL7. The 405 gr. Lyman has been hit and miss proposition. I suspect it mostly from my inability and lack of perseverance to do what is needed to make a plain base cast bullet perform.

For loading data I've been using the .45-70 loads listed for the Trap Door Springfield and for the Ruger No. 1 in the Hodgdon Data Manual No. 25. I've encountered no problems with excessive pressure, but I have not worked up to the top loads listed for the Ruger. I've stayed at least 3 grs. below the listed maximum. Accuracy with the better loads using H 4198 and RL7 has been in the 1.5" to 2" range. The best accuracy with the 405 PB cast bullet is in the 2-3" range at 50-75 yards."

From: The .45-70 Short 1.575", R. Wyble, The Fouling Shot, #173, Jan. - Feb. 2005

"What I needed was a shorter case, so after four generations of struggling with the .45-70 case size, a change was in order. I wanted a case just long enough to drive bullets between 400 and 550 grains to speeds not over 1300 f.p.s. This should be done with bullets sitting firmly on a .060" cork wad; some shorter bullets require two wads. All loads have a small amount of compression. The powders I use in the .45-70 are generally IMR4227, IMR4198, and Accurate Arms 2015BR. Others work but these seem to work best for me. IMR4198 is probably the best with heavy bullets using charges between 25-35 grains, depending on bullet weight.

Even though the new case would be shorter, I decided to leave my preferred powders the same, starting on the lower side of what I had been using for safety. For case length, I first looked at the .45-70x1.5" or .45 Silhouette, but it was designed to shoot 300-grain bullets. It is a little short on powder space and throat. At 1.575 inches I got enough space to do the job. So it became the .45-70 Short 1.575". Already having a Douglas Premium 1-20" .45 barrel blank and a Ruger M-77 that I've modified for rimmed cartridges helped the project along. This is kind of a one-way conversion for the M77 as the bolt face becomes different enough that you can't go back to a rimless cartridge without a new bolt. It is doubtful, in my case, that this would be desired, as I'm quite pleased with this rifle/cartridge combination.

…Not wanting to buy a custom reamer for such a simple conversion. I chanced upon a reamer specification sheet for the .458x2 inch from JGS Precision Tool in Oregon. According to the spec sheet, the first 1.575 inches of this reamer were in fact my .45-70x1.575. Even the throat was pretty close to what I wanted.

The reamer worked perfectly with the exception of the rim cut which I made separately. …I don't know if anybody else's .458-2 inch reamer would work. I don't even know if another one from JGS would work so well.

…I turned to loading dies, to see what problems there would be. The answer to this question is none. My RCBS dies work perfectly. Remington brass works best as it is thicker and the sizing die snugs them down just the right amount. The expander, when adjusted all the way down is right on the money, and so is the seating die. This is a plus, not needing any special dies.
…The bullet which has come out on top is the heavy Saeco 540-grain bore-rider. I think it was designed for the .458 Winchester and seems to fit my gun's throat very well. The powder for this heavy bullet is AA 2015BR. It's the hands down winner. Proper charge seems to be 28.6 grains behind a .060" cork wad with just a little compression. The only primers I use are Winchester Large Rifle magnum.

…The velocity is estimated at about 1200 fps with the 28.6-grain AA 2015 BR load.

…My best 100-yard group was .654 inches. At 200 yards, I turned in a best group of 1.439 inches."

From: .458-400 Express, J. Kronfeld, Handloader #187, June 1997

This was developed as a revolver cartridge by John Gallagher for use in a recylindered Ruger Blackhawk. The goal was a 400-grain cast or jacketed bullet at 1300 fps. The .45-70 case is shortened to 1.4" and used without neck-reaming. Hodgdon H110 was the only powder that gave the performance desired, but no load data was included in the article. Ballistics were about 10% better than the .475 Linebaugh.