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semi-automatic "470 Nitro" prototype

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26 October 2006, 07:52
MartytW
semi-automatic "470 Nitro" prototype
Greetings and Salutations -

I've been away from these boards for some time and even when I was here more frequently, I typically stuck to "Big Bore" and "Wildcat" forums. However, we just did the first round of testing of our new .470 Rhino caliber and it is meeting (if not exceeding) our expectations.

What is a .470 Rhino?
The case is a modified .500 Jeffery case, designed to function in an AR-10 or DPMS LR-300 series semi-automatic rifle. I realize these rifles are atypical for Big Game hunting, but perhaps that was also due to the lack of a cartridge that was truly suitable for big game.

Enough words, what about numbers?
480 gr Woodleigh, 24" barrel, 2,250 fps
500 gr Barnes RN solid, 24" bbl, 2,125 fps

That latter number puts it right next to .470 Nitro Express, which is what the customer who sponsored the project wanted.

More information, including pictures and video, can be found HERE

as well as on our website under "What's New"

We are looking to have brass made and are looking at the .416 and .375 versions next.

Perhaps somewhat unorthodox, but we felt this would be perhaps the ultimate back-up weapon for a guide/PH, with 8 rounds in a magazine ...

Hope y'all don't mind us sharing ...


Marty ter Weeme
Teppo Jutsu LLC
Home of the .458 SOCOM
www.teppojutsu.com
26 October 2006, 20:54
BigNate
I never thought you'd get the speed out of the Rhino line like you have. The .338 with 210gr partions nearly duplicates the velocities of the .338 WM and does equal the .338-06? That's viable. What kinds of pressures are you using?

An M4 size thumper like that might make a hell of a backup! I was just thinking about the .338 or .375 as a hunting rifle. Might be an interesting approach to a stalking rifle. Nate
26 October 2006, 21:11
MartytW
quote:
Originally posted by BigNate:
I never thought you'd get the speed out of the Rhino line like you have. The .338 with 210gr partions nearly duplicates the velocities of the .338 WM and does equal the .338-06? That's viable. What kinds of pressures are you using?

An M4 size thumper like that might make a hell of a backup! I was just thinking about the .338 or .375 as a hunting rifle. Might be an interesting approach to a stalking rifle. Nate


Nate -

We're using 55000 psi right now in our simulations, but actual peak pressure is likely to be lower - we need to make a test barrel to confirm.

As to the 338 version, my numbers show

338 Win Mag, Speer 225 BT SP, 24" bbl, 2944 fps (Speer #13 Manual)
338-06, same bullet, 23" bbl, 2678 fps
338 RUM, 250 A-frame, unknown bbl, 2860 fps (Remington data in COTW 11th Ed)

For the 338 Rhino, simulation at 55000 psi:

250 A-frame, 24" bbl, 2779 fps
Speer 225 BT SP, 24" bbl, 2950 fps

If we raise pressure (the case can take more) to 62000 psi, she will hang close to the 338 Lap Mag (which requires that same pressure to get its velocities)

All of these have to go in the larger AR-10 platform, not the M4 ... the high pressure loads (over 55) should be used in bolt guns only


Marty ter Weeme
Teppo Jutsu LLC
Home of the .458 SOCOM
www.teppojutsu.com