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Cartridge Profile:  470 Capstick

By Daniel McCarthy © 2004

originally published in African Hunter Magazine

As you look at a surplus military Mauser 98 and ponder what big bore to build, perhaps the 470 Capstick should be on the list.  It was named in honor of author Peter Hathaway Capstick, who was famous for his stories about hunting dangerous game in Africa.  Art Alphin of the A-Square Company (www.a-squarerifles.com) designed the 470 Capstick to have the biggest diameter bullet and the greatest powder capacity that can be squeezed out of the .375 H&H parent case.  It pushes a 500 grain .474” diameter bullet at a nominal velocity of 2400 f.p.s., making it a prime candidate for dangerous game hunting.

The Cartridge

The 470 Capstick is a belted magnum with the same rim and belt size as a .375 H&H.  The case has a length of 2.800 inches, and the overall cartridge length is 3.65 inches.  A cartridge drawing is shown below for dimensions.

The 470 Capstick will fit in the same length action as the 375 H&H and .458 Lott.  The photo at left below provides a comparison of the 470 Capstick to the 375 H&H and the 458 Lott cartridges.  Actually the .458 Lott is a good measuring stick for the 470 Capstick.  The Capstick has a bullet that has 7% more cross sectional area than the .458 Lott, which, in theory, would result in more shock transfer to game and a larger wound channel..  As for powder capacity and velocity, they are similar, with the 470 Capstick having a slight edge in powder capacity and therefore a slight edge in theoretical velocity. However, for field use the 470 Capstick and 458 Lott should have identical performance because the differences between them are rather small.

That being said, the differences in field results between the 458 Win. Mag. and the 470 Nitro Express should be nonexistent, because both push a 500 grain bullet at 2150 f.p.s.  But some people have noted an observable difference in the way shot game behaves with those two cartridges, possibly due to the greater cross sectional area of the .474” bullet. If desired, the 470 Capstick can be used to create a ballistic twin to the 470 Nitro Express, pushing a 500 grain bullet at 2150 f.p.s. while generating low pressure.

For those who remember the .475 Ackley, it is similar to the 470 Capstick, except that the Capstick has a ghost shoulder which allows the cartridge to achieve excellent accuracy.  Use of a ghost shoulder, rather than a continuous taper on the case wall, helps the cartridge to line up concentrically with the bore axis, contributing to accuracy. 

This target shows two sample groups shot with the 470 Capstick at 100 yards.  The left group measures 1/4” x 3/8” center to center, and the right measures 3/8” x 3/16”.  I have not been able to achieve similar accuracy with the .458 Lott, and my theory is that lesser accuracy from the Lott is due to the continuous taper and lack of a ghost shoulder in the Lott case.

Target with two different 3 shot groups fired from a 470 Capstick rifle at 100 yards.  The left group of 3 was shot using 500 grain Woodleigh soft points on top of 90.0 grains of Reloader 15 powder.  The right group of 3 was shot using 500 grain Woodleigh soft points on top of 85 grains of IMR 4064 powder.  This kind of accuracy can be attributed to fine gunsmithing and to the ghost shoulder on the .470 Capstick which helps to center the cartridge in the chamber and leads to an inherently accurate cartridge.

Although it is possible to use 600 grain bullets in the 470 Capstick cartridge, the powder capacity is not sufficient to push 600 grains at anything near 2300 f.p.s. without high pressure, so I do not think this is the best bullet weight for the Capstick.  500 grain bullets seem to be the best all-around compromise.  With full power loads, recoil is significant but not difficult to control or become accustomed to.  Recoil from the cast lead bullet load shown below is almost nonexistent.  For plinking or light game hunting, 400 grain pistol bullets are a candidate, but they generate almost as much recoil as 500 grain bullets.  The advantage of 400 grain bullets is that they are inexpensive and will open up quickly on light game.  In my rifle they also tend to hit at least 6 inches higher than the 500 grain bullets, creating an inconvenience for the hunter who wishes to use both bullets on the same hunting excursion.

Some sample loading data for the 470 Capstick is as follows:

The velocities were chronographed at 95 degrees Fahrenheit at 5000 feet elevation from a 26” Pac-Nor barrel.  Before loading for the 470 Capstick, the reader is encouraged to consult the A-Square reloading manual “Any Shot You Want” for complete reloading data.

The Rifles

Currently factory rifles in 470 Capstick are available from A-Square, from the Winchester Custom Shop and from Fuchs Fine Guns (www.jagdwaffe.com).  However, that short list should not disappoint the reader because there are many options for building a nice custom rifle in .470 Capstick.  Any action that can handle the .375 H&H is a suitable candidate. 

The easiest conversion is a CZ550 that came from the factory in .375 H&H, .458 Win. Mag or 458 Lott.  All that has to be done is to replace the barrel with another in 470 Capstick  Barrels are available from Lothar-Walther (www.lothar-walther.de) and Pac-Nor (www.pac-nor.com).  A 2^nd recoil lug must be added to the underside of the barrel and inletted into the forearm of the stock.  The 2^nd recoil lug will spread recoil that the stock is exposed to, across a wider surface area to avoid splitting the stock.  Glass or steel bedding is recommended.  Some minor polishing or adjusting of the ramp and rails may be needed, and then the rifle is ready to shoot.  The advantage of the CZ550 conversion is that they typically hold 5 rounds in the magazine box plus one in the chamber, and very little work is usually needed to get them to feed.

A Winchester Model 70 Classic (claw extractor) can also easily be converted to 470 Capstick.  In addition to the steps above, the magazine box spring must also be replaced with one that has a traditional Z-shape instead of the curly-Q style that the factory provides.  The Winchester conversion may only hold 2 cartridges in the magazine box, unless you purchase an extra deep magazine box and bottom metal from Sunny Hill (through www.brownells.com), Williams Firearms (http://www.williamsfirearms.com/)  Jim Wisner (http://www.wisnersinc.com/) or Ted Blackburn (801 373 3526)  Use of an extra deep magazine box necessitates replacement of the stock with another stock having greater depth of wood.  Alternatively, it may be possible to fit 3 rounds in a model 70 conversion with the factory magazine box if the follower is replaced with one having a lower profile, or if the follower is milled to shorten it. 

Another option and the one which I prefer, is to rebuild a surplus military Mauser 98 action to be a 470 Capstick dangerous game rifle.  This is a very involved project and includes replacing the magazine box/bottom metal, spring and follower and opening up the receiver to match it.  Further, some machining of the new magazine box may be needed, since no one makes a magazine box expressly intended to hold 4 rounds of 470 Capstick. Proper feeding is not easy to accomplish and requires a big bore expert such as Dennis Olson of Plains, Montana, to radically modify the rails and ramp.  A picture of a Mauser 98 in 470 Capstick is shown on the left. 

The stepped configuration of the feed rails of that rifle is shown below. The stepped feed rails plus a modified feed ramp, achieve smooth feeding of flat nosed solid bullets in this rifle.  Any of these routes can result in a very functional and very accurate dangerous game rifle.  The author’s personal preference of a Mauser 98 action is not the route for persons seeking a budget-oriented rifle, or for persons who do not have access to a gunsmith who is a genuine big bore expert.  Frankly speaking, there are not a lot of gunsmiths who know how to get a big bore to feed properly, making the CZ550 conversion very attractive because there is so little to do.

In the Field

The 470 Capstick is designed for use as a dangerous game cartridge but it has proven very useful on light game as well.  The key is to select a bullet suitable for the game.  If a bullet designed for use on cape buffalo is used on whitetails, it undoubtedly will not expand.  For light game, Hawk bullets which expand quickly or 400 grain pistol bullets may be best. When the 470 Capstick is loaded with a 500 grain bullet to a muzzle velocity of 2300 f.p.s. and sighted in 3 inches high at 100 yards, it is only about a foot low at 300 yards, giving it more effective range than many cartridges which are popular for deer and elk hunting.  I have lobbed 470 Capstick bullets into game at that range, so it cannot be too difficult.

Another consideration in choosing a bullet for hunting is the velocity window of the bullet.  For example, the 500 grain Woodleigh soft point is designed to expand at 470 Nitro Express velocities (2150 f.ps.), and if pushed to the 2400 f.p.s. potential of the 470 Capstick, the Woodleigh will tend to expand very quickly and sacrifice penetration.  To the right is a 500 grain Woodleigh soft nose fired from a 470 Capstick into a kudu, at less than 20 yards, with about 2350 f.p.s muzzle velocity.  The recovered bullet weighs exactly 400 grains and measures 1.02” x 0.72”. The Woodleigh soft nose was designed to expand at the lower velocities of the 470 Nitro Express, and the fact that it held together at all in the 470 Capstick is testimony to the Woodleigh’s toughness.  Penetration was just over 3 feet.

The author’s favorite .474” bullet, the 500 grain GS Custom flat nosed solid, penetrated through an elephant shoulder and reached more than 6 feet into the elephant before stopping.  Muzzle velocity was just over 2300 f.p.s. and the bullet was undeformed when recovered.  This is first class performance, but many of the other bullets discussed below are excellent choices as well.  Among solids, in general the flat nosed designs will typically transfer more shock to the animal, penetrate more deeply, and cut a cleaner hole in the animal for more rapid bleed out, compared to round nose bullets.

Bullets, Etc.

There are many bullets available that can be used in the 470 Capstick, as shown in the table below.

It is noteworthy that the driving band bullet designs, such as GS Custom, North Fork and Bridger, engrave on the rifling with very little pressure, allowing them to be loaded with a greater powder charge for greater peak velocity.  The other benefit of this design is that it does not tend to foul the barrel, in contrast with the Barnes X-bullet, Trophy Bonded Bearclaw, and Swift A-Frame which foul some barrels very quickly.  Barnes has reduced but not eliminated this problem in their newer solids and Triple Shock bullets which have several large grooves in them.  However, the bands between the grooves are so large that significant barrels stresses are still likely to be created, and some users are still reporting significant barrel fouling, although accuracy seems to have improved over the prior version of Barnes bullets.

Cases for the 470 Capstick are available from a variety of sources.  Properly headstamped brass can be purchased from Huntingtons (www.huntingtons.com), A-Square, Quality Cartridge (http://qual-cart.com/) and Dieter Horneber (http://www.huelsen-horneber.de/).  375 cylindrical brass can also be used (available from Huntingtons).  Alternativey, the reloader can fireform his own brass from .375 H&H, .416 Remington or .458 Lott. 

Dies for the 470 Capstick may be purchased from Redding (www.reddingreloading.com), RCBS (www.rcbs.com) or CH4D (www.ch4d.com). For the shooter desiring factory ammunition, A-Square, Superior Ammo (www.superiorammo.com), Safari Arms (www.safariarms.com) and Quality Cartridge support the 470 Capstick with dangerous game ammo. 

Conclusion

For those who like the road less traveled, the 470 Capstick may be a nice alternative to some of the more mundane factory big bore offerings.  It can be used to duplicate either the 470 Nitro Express or the 458 Lott but offers greater frontal cross sectional area than the 458 Lott.  Accuracy with the cartridge is excellent, and an inexpensive 6 shot repeater can be made from the CZ550, in a simple rebarreling project.  Alternatively, a Model 70 or a Mauser 98 can be the basis of a 470 Capstick rifle.  The trajectory of this cartridge is better than you may expect, and the field performance is excellent.  It may be worth a look.