.240 Weatherby Magnum: The Hotrod 6mm

By John Johnston

In 1968 Roy Weatherby designed and created his last Weatherby magnum cartridge. The .240 was born to compete with the .240 H&H. Typical of Roy Weatherby's prior rounds, the .240 had a belted case. It has survived for all these years, but its future may be in doubt. Like most of Weatherby's cartridges, the cost of .240 ammunition and brass is rather expensive. Norma makes the brass with the Weatherby head stamp plus the loaded ammunition. Depending on the bullet used in the ammunition, a box of Weatherby .240 Magnum runs as high as $90.00. The round begs to be reloaded to gain the best accuracy and velocities. Once you get past the cost of brass, a reloader can enjoy this cartridge with no financial guilt. The same brass selling under the Norma name is slightly less expensive. Dies by many of the top companies are readily available.


Weatherby Vanguard S2

Some claim that the .240 will shoot the same bullet 150 feet per second faster than a 6mm Remington or the .243 WSSM. In my own tests I found that 150 FPS may be a slight exaggeration shooting with a Weatherby Vanguard S2 with a twenty-four inch barrel. I did not have a .243 WSSM in my safe but I had my own reloading file from a previous test. My figures showed the WSSM shot the lighter grain bullets up to 80 grains at the same or slightly higher velocities than the .240. I have tons of experience and loads with the 6mm Remington. I found that the .240 was faster. I choose 6mm Remington for Texas whitetails and long range shooting out to six hundred yards. With factory 85gr. ammunition at five hundred yards the .240 shot six inches higher than the 6mm Remington and one and a half inches higher than the .243 WSSM.


The .240 at the range.

The Vanguard S2 is the least expensive Weatherby. It is made in Japan by Howa. Weatherby guarantees the rifle to shoot one inch or better. It is a nice rifle with a suggested retail of $649.00. The barrel is 24 inch hammer forged and has a 1-10 inch barrel twist. The bolt is a two lug style. The action has a three position safety. The two stage trigger is user adjustable down to 2.5 pounds and breaks rather nicely, even for my picky tastes. The stock is made of a material which Weatherby calls "Griptonite". To me it feels like a Hogue over molded stock. The bedding is molded in to the stock. The recoil lug has a slight taper. This helps keep it snug.

I sighted in the rifle with a Vortex Viper 4x16 with a Dead Hold BDC reticle. I found this model Vortex very suitable for my style of shooting. The glass was clear and bright. At the shooting range I found the turrets were accurate and went back to zero. My reloading began; I started by trying to find the weight range of bullets which the rifle preferred. Trying bullets from 65gr. to 105gr. it became apparent the rifle liked bullets in the 80 gr to 95 gr. range. The 100 Sierra and Berger 105gr could not get groups less than 1.27 inches. I reached the sweet spot with the 80gr. Barnes TSX pushed to a velocity of 3569 FPS with a load of RL-17. This load shot several 0.50 inch four shot groups at 100 yards.


Not much to the bedding.

That weight bullet should have been able to be pushed over 3600 FPS but I found any attempts to use more powder showed very slight signs of high pressure, with primer cratering. I even tried primers from CCI to Winchester in both magnum and regular. I believe a lot of the test rifles used to develop these 3600+FPS loads, which people speak of, had 26 inch barrels. If you reload for this caliber make sure that you are aware that it can develop velocities higher than what some bullets can withstand. The bullets can disintegrate in midair or they may not stabilize. Nosler, for example, does not recommend velocities over 3200 FPS for their Accubond Long Range 6mm bullet.


L to R .243, 6mm Rem., .240 and 6XC

Prior to the arrival of this rifle, I had read that the recoil and muzzle blast of this round were uncomfortable for the shooter. In shooting this rifle I did not have either problem. The stock handled recoil very well and muzzle blast was normal for this size round. Not surprisingly, extended strings of shots tended to open up groups. I found that in the Texas heat, four rounds were the most I could shoot without overheating the barrel. This may be a problem for prairie dog shooters.

Long range shooting showed me that my pet 80gr. TSX load was good out to 500 yards. At 750 yards it was difficult to hit the steel plate. This may be because of stiff wind from right to left, the light weight of the bullet or it may have been just my shooting. I was pleased with this rifle's accuracy. The .240 Weatherby Magnum round is very capable if you need a fast 6mm without going to a wildcat. Like the .243WSSM the barrel life may not be too long. However due to the .240 case design I believe the barrel will last longer than the .243WSSM but not as long as a .243 Winchester or 6mm Remington. Of course all this depends on your shooting habits.

Weatherby claims this rifle will shoot MOA and that is accurate. Each .240 rifle will have a sweet spot in regards to bullet type, weight and velocity. In general I found bullets achieved maximum accuracy potential at the higher velocities. The powders that worked the best were RL17 and RL22. The .240 Weatherby Magnum can be a fine round for deer, antelope and varmints.

A rifle enthusiast has to wonder what Roy Weatherby and P.O. Ackley could have come up with together. Remember that you may have slightly different results with this cartridge. Start all loads low. Work up to the velocity you desire.

After twenty-five years with a major law enforcement agency, John Johnston retired to the hill country of central Texas. His law enforcement career was diverse with assignments with the tactical/motorcycle unit, patrol, and criminal investigation. After retiring, writing became his calling. He started with a newspaper column which, he still writes and then moved up to major magazines in the area of shooting and hunting. He is known for his unbiased product testing and evaluations. Having a full size range from 25-450 yards next to his home was his dream come true. 2010 marks his fiftieth anniversary in the hunting, shooting and reloading sports. You will notice his writing style is quite relaxed and he prefers to write like he is speaking to you around a camp fire. John welcomes questions and comments whether good or bad. You can reach John at [email protected].