The Pancor MK3A1 or Jackhammer is a 12-gauge, gas-operated, fully automatic shotgun. It was developed by John Anderson in 1984 and patented in 1987. While the Jackhammer did reasonably well in its military trials (firing over 50,000 rounds without issue), it had various issues that kept it from being accepted; such as the lack of ejector, large frame, low magazine capacity, and, most of all, the designer's lack of funds to further the project. It is not clear how many guns were made as it never left the prototype stage, but there is just one functional prototype in existence as the rest were sold to other countries and disappeared or destroyed.
— In-game description
The MK3A1 is a weapon featured in Battlefield 2 as the Tier one unlock for the Engineer Kit. It is the only full-automatic shotgun, and fires from a seven-round magazine. It is significantly less powerful than the pump-action shotguns or the Benelli M4, although it shares their long reload pattern.
The MK3A1 is a weapon featured in Battlefield Play4Free. It can be purchased for a price of 120,000 Play4Free Funds or obtained as a gift. It holds ten 12-gauge shells and is fully-automatic.
— Battlelog description
The MK3A1 is a weapon introduced in the Battlefield 3: Back to Karkand expansion and is unlocked upon the completion of the Scarred Veteran assignment. It has more ammunition than the USAS-12 when equipped with extended magazines with 12+1 rounds available. It has high recoil if fired fully auto while aimed down the sight, but only after the first 3-4 shots. The ammo specialization is highly recommended, as the MK3A1 uses ammo very quickly.
Compared to its closest counterpart, the USAS-12, it has the same base accuracy and pellet spread, but benefits from firing 1 extra pellet per shot for a total 8, in exchange for having a lower rate of fire as well as a slower reload. Battlefield Premium members can equip the Airman and Woodland camouflages to the weapon upon the completion of the MK3A1 Specialist assignment.
- Upon unlocking extended magazines, an extended tubular magazine is displayed onscreen. This is odd, considering that the MK3A1 has a cylindrical magazine.
- The MK3A1 is the only shotgun that does not change visually when equipped with a flash suppressor.
- The ACOG, when equipped on this weapon showed the PK-A's reticule but, retained the zoom (this has since been patched).
- Before the March 2012 patch, the MK3A1 had a strange clicking in the reload sound that would have been played when the player attempted to insert a fresh magazine.
- It shared the same firing sound as the USAS-12 and had rifle crosshairs prior to the March 2012 patch.
- The suppressor, when equipped, failed to affect the weapon at all.
- After the March patch, when firing full auto, the recoil animation disappears, showing the muzzle climb without any shaking. This can be countered by quickly tapping the fire button.
- After the June 2012 patch, the ammunition capacity was increased to 8+1.
- Even if the MK3A1 does not eject empty shells like a revolver, a sound of one or more shells bouncing on the ground can be heard.