BAE’s Bofors 40mm Mk4 –Navy Lookout

BAE Bofors 40mm/70 mk4. Click on this to enlarge. Hight of the mount is 1.9 meters or 6.32 feet.

Navy Lookout has what may be the best evaluation of the BAE Bofors 40mm/70 Mk4 mount I have seen thus far. It looks at the 40mm Mk4 in the context of it’s planned installation on the Type 31 frigate, which will also mount the same 57mm Mk 110 gun being mounted on large Coast Guard Cutters (also a BAE Bofors product).

The system can use the same 3P (Pre-fragmented, Programable, Proximity) fuse that can be used with the 57mm Mk110 mount.

Consideration is given to the mount’s role in lieu of a dedicated Close In Weapon System (CIWS). A notable feature is that the 40mm Mk4 is 60% lighter than a Phalanx mount, 5,500 pounds (including about 540 pounds of ammunition) vs 13,600 (2,500 vs 6,120 kg). The Mk38 Mod3 by comparison is 2,300 lbs. (1,042 kg). The DS30M which is apparently expected to be the Mk38 Mod4 is DS30: 2,645 lbs. (1,200 kg) with ammunition.

Compared to the 30mm guns the Royal Navy is currently using, “40-mm weapons offer significantly longer ranges, increased lethal effect in anti-aircraft/missile and anti-surface engagements.”

Effective range is more than doubled and the 40mm projectile is about 2.7 times larger than that of a 30mm Bushmaster II chain gun and more than five times larger than the 25mm fired by the Mk38.

As noted, the 40mm/70 Mk4 has a number of competitors,

“Offerings from other European manufacturers include the Thales/Nexter Rapid Fire CTA 40 (France), Lenardo Marlin 40 (Italy), Rheinmetall Millenium GDM-008 (Germany) and the Aselsan Gökdeniz (Turkey). “

To which I would add the 40 and 50mm chain gun although they currently have no deployed naval mount.

The vessel in the video is 150 tons full load and 36.53 meters (120′) in length, very similar in size to the 153 ton full load Island class cutters. Originally it was a missile boat armed with a 57mm gun and up to six Penguin Anti-ship missiles.

Thanks to Lee for bringing this to my attention. 

5 thoughts on “BAE’s Bofors 40mm Mk4 –Navy Lookout

  1. The “Achilles Heel” of the 40x364mmR/70 gun is it’s rate of fire at ~330rpm (~5.5rps). Being that the barrel isn’t waterjacked it seldom operates above ~120rpm (~2rps)…

      • Looking at “Navweaps” I couldn’t find a travers rate for the Mk.4 as only being “Continuous Turning” without “Deg/Sec”. So I don’t know how fast it can actually engage another target after dispatching the first target…

  2. CTA40 is supposedly an Anglo-French weapon. One of those joint project with the Gauls were we Brits put a lot of effort and treasure into it and they the French reap all the benefit.

    • CTA ammunition can be had in many countries including the United States! But Royal Ordnance of the UK produces it, Nammo of the Netherlands and Rheinmetall of Germany also produce it just to name a few…

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