Amphibious Combat Vehicle (ACV) tested with a 40mm cannon...via Defense 24...

via Defense 24

The vehicles may also potentially use more armament than their predecessors. US media outlets recently announced that a 40 mm cannon is being tested on the ACV platform. The gun, over the course of the test programme, was being used against a myriad of different targets, from infantry (at longer ranges than usual), pick-up trucks, to heavier vehicles or UAVs. The cannon is to be able to hit and neutralize any of those threats. This would translate into creation of a set of better defensive abilities for the landing operations.

Northrop Grumman confirmed that ACV was being tested with the Bushmaster II Mk 44/S cannon in “stretch” configuration. The gun makes it possible to utilize the Mk 310 Programmable Air Bursting Munition (PABM) rounds. Mk 44/S is a 30 mm gun in its standard variant but it may be rapidly converted to the 40 mm calibre. ACV was tested with the “Stretch” 40 mm gun at least once, as reported by the US media. The tests took place during a recent conference gathering the Bushmaster cannon users. ACV is using the MCT-30 turret manufactured by Kongsberg.

Poland can also be find among the Bushmaster user group (Mk 44 Bushmaster II). The weapon is being utilized on the Rosomak APC. The “Stretch” variant is used on the WB Electronics/HSW ZSSW-30 turrets that are to become the armament on the newly delivered Rosomak APCs and Borsuk IFVs.

The available data suggests that USMC has not directly defined use of the 40 mm calibre as a requirement. The US Marines however, are interested in the Mk 44/S gun and the option of utilizing programmable rounds. Potential transition to the 40 mm ammunition is also being considered. The ability to maintain and manufacture the “Stretch” gun is to be established at the Polish HSW S.A. facility, within the scope of the offset arrangements made during phase I of the Wisła programme.

Story here. 

Missed this but I cheer.

HQMC is taking a look at a 40mm cannon. 

Good God!  The Marine Corps is getting its groove back!  This would be a nice long term "interim" caliber.  Effective for the foreseeable future and we can keep an eye on what the Army is doing with the 50mm.

Someone is working this problem to perfection.  Love it!