Impala Bullets Impala Bullets


One round for all needs

10,4X62 IMPALA - the universal caliber - a short review

10,4X62 Impala, left with 21g(325gr) RN bullet,
right with 15,2g(235gr) LS bullet

left to right: 9,3X62 (250gr RN ) - 10,4X62 LS -
10,4X62 RN - .375H&H Mag. (270gr RN)

With the 10,4X62 I created a cartridge to fit all hunting situations, worldwide. With over 4250 ft lbs.(5700 Joule) of muzzle energy it rivals the venerable .375H&H Mag. The heavier 325gr bullet of .400 caliber in combination with its larger frontal area gives the 10,4X62 Impala an edge when it comes to stopping power.* On the other hand the 235gr (15,2g) Light Solid at almost 2900 fp delivers .30-06 like tracectory with a point blank range well over 200 yards. This makes the big round even suitable for long shots in open or mountainous terrain. Felt recoil with the light bullet is comparable to a 9,3X62 or .35 Whelen.

Taylor RN Factor: .375  H&H Mag. 300gr (19,4g)  at 2560 fps ( 780m/sec).........41,1
                             10,4X62 Impala 325gr (21g) at 2430 fps ( 740 m/sec).........46,3


The idea is not new at all. If you want a big game cartridge to fit into standard Mauser 98 systems without expensive fitting you have to stick with the 11,95mm "Mauser" case head and a maximum COAL of approx. 84mm (3,3"). Then again the maximum diameter a .30-06 case can be necked up to maintain proper headspace is .411" or 10,4mm. In the July 1998 issue of the German "Deutsches Waffen Journal" gun magazin I broght a very detailed review of the .400 Brown Whelen cartridge.The wildcat cartridge described herein is, with conventional hunting bullets, a short range big game round . I managed to kill a cape buffalo in Tansania with a 350gr Swift A-Frame bullet without any problem.With the flat shooting 235gr Impala LS bullet the cartridge gains a lot of versatility and clean kills way beyond 200 yards are easy to manage. With this combination I successfully hunted plains game from Impala up to Hartebeest and Kudu in South Africa and was enthusiastic about its "knock down" performance.

Entering the 10,4X62 Impala project my main concern was the cartridge case. Beeing a .30-06 derivate the case can easily be fireformed from either .35 Whelen or 9,3X62 brass, but would it be possible to draw new cases with this extreme shoulder dimension? To my pleasent surprise German custom case maker Dieter Horneber of Fürth was able to create the tiny 40° shoulder with his hydraulic drawing machine.

The much bigger problem, as it turned out, was to settle for case and chamber dimensions. With the .400 Whelen, .400 Whelen Improved, .400 Brown Whelen and .411 Hawk there  already exist 4 very similar cartridges. I decided for the .400 Brown Whelen but had to find out that, as not unkommon with wildcats, there was a mess of different dimensions for chambers, reamers, headspace gauges etc. So, with friendly support from the Vienna Proofhouse, I set the dimensions according to my version of the .400 Brown Whelen and, to avoid any mix ups, choose the metric designation 10,4X62 Impala for the cartridge and put it in for CIP registration.

High Performance even at low chamber pressure

Finally the day came wehere the pressure test barrel at the proof house was finnished and we were able to measure the first rounds. Immediately the new round showed its potential.
With less than 60grains of powder the 10,4X62 Impala outperformes much bigger Magnums and it does it at lower pressure, too. When it comes to efficiency the cartridge stands second to none!

My "buffalo load" with the 350gr A- Frame bullet gave 2231 fps (680m/s) at only 52475 psi.(3618bar) for 2592 ft lbs. (5244 Joule) of muzzle energy.

Even more efficient were, expectedly, the Impala Solids. My profen "South Africa Load" sent the 235gr LS at 2723fps (830m/s) at a moderate pressure of 48414psi (3338bar) and respectable 3869 ft lbs. (5246 J). The first test load with the 325gr RN bullet brought a pressure reading as low as 42206psi (2910 bar). And at 2257fps (688m/s)  and 3677 ft.lbs.
(4985J) the load was nothing to sneeze at. I am already planning a rimmed version- 10,4X62R-Impala- for combination guns ith amaximum working pressure of 53664psi (3700bar).

Finally I developed 2 factory loads for the 10,4X62 Impala. See ballistics below:

235gr/15,2g Impala-LS /barrel length 24"      * 192yards     point blank range= 220 yards

Distance yards 0 50 100 150 200 250 300
Velocity fps 2854 2683 2537 2386 2241 2101 1965
Energy ft.lbs 4251 3784 3358 2971 2621 2303 2015
bullet path inches -2 +0,4 +1,5 +1,3 -0,4 -3,9 -9,2

Entfernung (m) 0 50 100 150 200 250 300
Geschwindigkeit (m/s) 870 816 765 715 667 621 576
Energie (J) 5763 5074 4451 4163 3384 2935 2530
GEE* 174 m (cm)   +1,3 +3,9 +2,4 -4,0 -15,9 33,8

325gr/21g Impala-RN /barrel length 24"      * 163 yards    point blank range = 186 yards

Distance yards 0 50 100 150 200 250 300
Velocity fps 2428 2255 2089 1929 1778 1637 1504
Energy ft.lbs 4251 3688 3148 2686 2282 1935 1633
bullet path inches -2 +0,7 +1,6 +0,6 -2,8 -9,0 -18,4

Entfernung (m) 0 50 100 150 200 250 300
Geschwindigkeit (m/s) 740 682 627 575 526 480 437
Energie (J) 5767 4904 4145 3480 2910 2424 2014
GEE* 148 m (cm)   +2,1 +3,9 -0,3 -12,4 -33,4 -64,5

* most recommended sight in range

Accuracy: Five shot groups under 1,5" at 100yards with factory ammunition are the rule and some handloads are doing even better.
We are talking about groups shot with my rifle (4X scope) from the shoulder.

Availability of guns and ammuntion:

The 10,4X62 Impala was introduced to the public at the "Jagd und Hund" trade fare in Dortmund (Germany) from Feb. 4-10,2008)

Factory cartridges: The 2 loadings listed above are available  through licensed dealers since Feb. 2008

Cases: New, unprimed 10,4X62 Impala cases are available since Feb. 2008 directly from Impala Europe or licensed gun dealers

Guns: As of Feb. 2008 there exist 2 custom Mausers, two more beeing under construction. At the  trade fares to come  the new round will be introduced to all major manufacturers of hunting rifles.

Barrels: Ready to fit in  Mc Gowen  barrels are available through Impala Europe. Delivery time  is approx. 4-6 weeks.

Reloading dies: Use  RCBS  .400 Brown Whelen  dies for best results

More information available at  or contact me directly at (