The .470 and .475 Turnbull Lever Action Rifle Cartridges
By Chuck Hawks
In 2007 Doug Turnbull, of firearm restoration fame, began work on a couple of big bore cartridges for lever action rifles. The .470 is for Marlin Model 1895 actions and the .475 is for Winchester Model 1886 actions of either vintage or new manufacture. (Turnbull Mfg. makes extremely high quality Model 1886 reproductions with 100% original parts interchangeability.) The .475 Turnbull is also available in a special edition of the Ruger No. 1-H Tropical falling block, single shot rifle.
The primary lure of proprietary cartridges like the .470 and .475 are their uniqueness. Not every hunter in camp will have one.
Back in the day, Winchester contemplated a .46 WCF cartridge for the Model '86, but the idea was never developed to fruition. This was part of Turnbull's motivation, "because it didn't exist." Doug chose to use .475" bullets, because the continuing popularity of the old .470 NE meant that good, modern bullets are available in the caliber.
Turnbull developed the .475 specifically for the Model 1886 action. The Winchester action is longer than the Marlin 1895 action and the .475 cartridge will not fit in a Marlin. The .470, developed at the request of Marlin fans after the successful introduction of the .475, is a shortened version designed to work in the Marlin 1895 action. According to the Turnbull Mfg. website, ".470 Turnbull conversions can be made to either original rifles or the new production Model 1895 Marlin rifles."
Doug told me that vintage Marlin 1895 and Winchester 1886 actions are strong enough to handle the 40,000-42,000 psi developed by these new Turnbull cartridges. It is the old barrels, not manufactured from modern nickel steel alloys, which fail if one "hot-rods" cartridges. (The old barrels blow at the bottom, just in front of the receiver, where the magazine tube intrudes.) Therefore, when converting a vintage action to a Turnbull cartridge, the first requirement is rebarreling. Turnbull also carefully fits the actions to ensure reliable operation with high pressure, bottleneck cartridges.
Both cartridges are based on rimmed, bottle-neck cases with diminutive shoulders and use .475" diameter bullets. The .475 is based on what is essentially a blown-out, necked-up .348 Winchester case. The .348 was itself based on a shortened (2.25") and necked-down version of the longer (2.4") .50-110 Winchester case. The .470 is also based on the .348 case. MAP is specified as 42,000 psi for the SAAMI standardized .475 and about 40,000 psi for the .470, which has not been SAAMI certified.
The .475 Turnbull has a .610" rim diameter, .070 rim thickness, 548" base diameter, .538" shoulder diameter, 17-degree 15-minute shoulder angle and .502" neck diameter. Case length is 2.20" and the maximum cartridge overall length is 2.78".
The .470 Turnbull has a .610" rim diameter, .070 rim thickness, 548" base diameter, .520" shoulder diameter, 10-degree shoulder angle and .502" neck diameter. Case length is 2.05" and the maximum cartridge overall length is 2.55".
Because both cartridges are designed for use in rifles with tubular magazines, only flat point or round nose bullets are used. The bullets sold by Turnbull Mfg. (www.turnbullmfg.com) are manufactured by Barnes (TSX and solid), Nosler (solid) and Hawk (soft point). The Barnes bullets cost $125 per 100, the Noslers are $200 per 100 and the Hawk soft copper jacketed soft points are $75 for 50 bullets ($150/100). These are 2012 prices direct from Turnbull. .475" bullets are also offered by Woodleigh and Speer. Reloading data for both cartridges, including data for reduced power .475 loads, is available on the Turnbull Mfg. website in the form of PDF files.
Properly headstamped brass and reloading dies (either RCBS or Hornady brand with shell holder) are available from Turnbull Mfg. The prices are as follows: RCBS dies, $275; Hornady dies, $225; brass (box of 20), $30.
SAAMI certified .475 Turnbull factory loaded ammunition is available from Cor-Bon. A box of 20 Cor-Bon DPX or Hunter 400 grain factory loads runs slightly in excess of $89. At about $4.45/shot, .475 factory loads are not inexpensive!
Here are the claimed muzzle velocity (MV) and muzzle energy (ME) for the two cartridges from 26" barrels:
As you can see, the .475's velocities are about 200 fps faster than Ruger No. 1 .45-70 +P loads and about 200 fps shy of the .458 Winchester Magnum. Any reloader with a .458 rifle can easily duplicate .475 Turnbull velocities and energies with reduced power handloads. For example, I load a 400 grain bullet at 2050 fps in my Safari Grade .458 for hunting the largest North American game. Of course, the .458 Win. was designed for magnum bolt actions and is not available in a lever action rifle.
The .470's ballistics are quite similar to the .450 Marlin (350 grains at 2100 fps or 400 grains at about 1950 fps) and one can accomplish the same thing with a standard .450 Marlin rifle at far less cost. .450 Marlin factory loads are less expensive and widely available, a big advantage for most hunters.
An added benefit is that the .450 Marlin and .458 Win. Mag. cartridges use standard .458" diameter bullets, available to reloaders everywhere, that offer superior sectional density (SD) for any given bullet weight. For comparison, the SD of a 500 grain .475" bullet is about .317, while the SD of a 500 grain .458" bullet is .341. Other things being equal, the bullet with greater SD will penetrate deeper. However, these are both excellent numbers. Bullets with a SD of .300 or better are generally regarded as suitable for thick-skinned CXP4 game.
In the field, the .47 caliber Turnbull cartridges have proven to offer plenty of penetration for even the largest animals. The Turnbull Mfg. website has an online "photo album" featuring big animals harvested with .470 and .475 rifles. If you have always hankered to drop a pachyderm with a traditional lever action rifle, a Turnbull Mfg. Model 1886 in .475 caliber is the way to go.
The .470 and .475 Turnbull are powerful cartridges and kick accordingly. Like the .450 Marlin, the .470 Turnbull is not for the timid. In rifles of the same weight, launching bullets of the same weight at approximately the same MV, the recoil of a .470 Turnbull and .450 Marlin are essentially indistinguishable.
Personally, I can't imagine shooting full power .475 loads in a Turnbull Mfg. "Standard Grade" Model 1886 rifle, whose stock mimics the old Winchester design. This incorporates plenty of drop and comes with a traditional steel, crescent butt plate that minimizes the shoulder contact area. Turnbull's bespoke "Deluxe Grade" rifles are usually stocked with much less drop and supplied with "shotgun" butts and a recoil pad to help moderate the felt recoil.
Due to the Marlin 1895's solid top receiver, it is easy to mount a scope on a .470 lever action. Because the .470 is a relatively short range cartridge, a low power, wide field optic in the 2x range should be sufficient.
The Winchester 1886 is a top ejecting design, which precludes normal scope mounting. These rifles are designed for use with iron sights, which are supplied.
The .475 Ruger No. 1-H comes with scope rings and a stock designed primarily for use with telescopic sights. This classic, but modern, rifle would be ideal for older shooters or anyone whose eyes lack the accommodation required for precision shooting with iron sights. A 1-4x variable power scope should fill the bill.
Turnbull also rebarrels and modifies Browning Model 71 rifles to accept the .475 cartridge. Like the Model 1886, the Model 71 rifle is designed for use with iron sights. Modifying a customer supplied rifle costs approximately $3200; built to order on a Turnbull supplied rifle, the price is approximately $4995.
Before closing, I need to thank Doug Turnbull for taking the time to discuss his .470 and .475 cartridges for this article. Doug is one of the good guys in our industry.
If I could own a rifle in .475 Turnbull caliber, I'd choose the Ruger No. 1 option. As of this writing, Turnbull Mfg. is selling standard No. 1-H rifles for $1100. Turnbull Mfg. also offers completely refinished No. 1's with a color case hardened receiver, lever, quarter rib and scope rings; rust blued 26" barrel and refinished walnut stock for only $2000. These are beautiful rifles and, considering the workmanship, very reasonably priced.
Copyright 2012 by Chuck Hawks. All rights reserved.