The Weatherby Mark V Magnum rifle (mostly just referred to as “Weatherby”) is a push-fed, bolt action rifle developed by Roy Weatherby in 1957. Roy Weatherby designed the Mark V for his .378 Weatherby Magnum cartridge.
The development of the Mark V was inspired by the need for a bigger cartridge and a stronger rifle to chamber this new cartridge.
The original cartridge was the .375 Weatherby Magnum. An improved .375 H&H Magnum created by blowing out the case walls for maximum case capacity with the trade mark double radius shoulders. Although this wildcat did improve on bullet velocity and impact energy, Roy Weatherby wanted more. He then went to a larger capacity case. He settled on a necked down version of a .416 Rigby with a belt and thicker walls to handle the greater internal presser. The double radius shoulder was also incorporated.
Now Roy Weatherby had a cartridge to build his rifle around. The first unique design feature was a new bolt design. Normally a gun maker would take an existing action and open up the bolt face to the accommodate a larger rim size. Roy Weatherby decided to go in the other direction. He started with a larger bolt body. The new bolt differed from the standard bolt as it did not use two external lugs. The new bolt design was to mill four square cut grooves circularly around the bolt body just behind the bolt face. These grooves left three rings. The rings were then milled with three square cut longitudinal grooves creating three rows of three lugs for a total of nine lugs.
This new design lead to 5 new innovations:
- The 3 lug design created a short bolt throw for faster reloading; 60 degrees (nominally) rather than the 90 degrees (nominally) of the 2 lug design.
- The inlet lug design took the horizontal slop out of the bolt that was caused by the two channels milled into receiver body for the horizontally placed outboard 2 lug design.
- With no channels milled into the receiver for exterior facing lugs and having 9 baring lug rather than 2, the receiver and bolt system is stronger.
- Because the bolt has the lugs milled into it, the large belted case of the .378 Weatherby. Magnum can fit comfortably in a receiver designed for a .375 H&H Magnum size receiver.
- The bolt is one piece for strength, fluted to reduce friction and drilled with 3 gas vents for safety.
The stock of the Mark V also diverges from the classical American style of a straight stock. The Mark V stock is called a “Monte Carlo” style stock and incorporated these 3 new features:
- A high comb and dropped heel for more comfortable off-hand shooting with optical sights.
- A more pronounced hook in the pistol grip for a better hand hold.
- A larger and more meaty stock to handle the increased recoil energy to the rifle and lessen the felt recoil to the shooter.
The Mark V rifle was manufactured in Germany (Bavaria) from 1958 to 1995 and from 1995 to present in Japan.
The Mark V rifle is chambered in all the large cartridges based on the .378 Weatherby Magnum case, the small cartridges based on the .300 H&H Magnum case and several standard commercial cases. There are 8 Mark V models.