<XMP><BODY></xmp> 25mm Musings

25mm Musings

When I was writing my page on the .50 HMG Ralph Zumbro pointed out to me the interesting fact that the case of the Browning machine gun round was nearly an inch in diameter, so could theoretically could be opened out to accept a larger calibre projectile. The 25mm OCSW was in the advanced trials stage, so there didn't seem to be any realistic practical application for this piece of information.

        The OCSW was originally intended to replace both the .50 HMG and the 40mm HV Mk-19 Grenade launcher. As I've pointed out elsewhere, while this weapon may do a very credible job at replacing the Mk-19, it is unlikely to be as effective as the .50 HMG against fast moving distant targets. On other pages I've suggested that a saboted sub-calibre round might need to be developed for the OCSW.

        Recently a friend of mine mentioned that sometime in the past year he'd read an article about a US army requirement for a weapon to replace both the HMG and the Mk-19. Concept was to have a basic weapon that could be configured to fire either .50 calibre bullets or 25mm grenades just by changing a few components. It's possible that the author of the article is getting mixed up with the OCSW, but let's assume that this is not the case. Certainly there is a requirement for such a weapon in addition to the OCSW.

        How practical is the idea of a HMG and a grenade launcher with most of their parts in common? We need look no further than the Czech B-30 and B-40. One is a 12.7mm semi-automatic AMR, the other a magazine fed grenade launcher firing the Russian 30mm HV grenade. A B-40 can be changed into a B-30 just by changing a few components. Singapore has developed a 40mm HV AGL of just 14kgs weight, and this gives us some idea of how light a .50/25mm weapon might be if designed along similar lines.

        It would make a lot of sense if the new heavy support weapon used existing .50 HMG rounds for its machine gun mission. The grenade round would use a case that externally matches the dimensions of the .50 BHMG round but mounting the same grenade as has been developed for the OCSW.

        An idea that my friend Ed Sackett is fond of is the concept of firing a shotgun type round from the .50 HMG. In situations where engagement ranges are relatively short this idea has considerable merit. The long range and high penetration of conventional rounds can make them very dangerous to both allies and non-combatants. Multiple projectile rounds should be designed in both .50 and 25mm rounds.

UPDATE We can take this idea to a more logical conclusion, and have a BMG case mounting either 25mm-type Grenades, saboted high-velocity KE rounds or multiple projectile rounds, all firing from the same barrel and weapon. In essence a bigger version of the M2030 concept and the Hose

Further Update: A .50 calibre machine gun based on the OCSW is being developed.
GD site on the .50 XM312
        The General Dynamics site also mentions that the 25mm OCSW XM307 can be converted into a .50 HMG.

        Another interesting thing that I've recently come across is that Barrett (famous for the .50 AMRs) have been asked to develop a "Payload rifle" firing the same round as the OCSW. Concept seems to be the OCSW will program the rounds it fires to airburst, while the Payload rifle will use "dumb " rounds using impact-detonated fuses.

        On his webpage, Dino Snider makes an interesting case for an updated shotgun shell based on a 30mm case. The Russians already have a 23mm/6 bore weapon.

         Dino's proposal is for a wider bore with a more reasonable charge to form a modern blunderbuss of about 1" (25.4mm) calibre. Mightn't such a case also chamber the same grenades as the payload rifle, I wondered? The answer is that the Payload rifle projectiles would be too long, but this did suggest to me that a 25-28mm weapon with canister and explosive rounds would prove to be a very useful CQB and MOUT weapon, and would nicely complement the Recoilless Grenade Launchers that I've proposed.

        More on my idea for a modern Blunderbuss on this page.

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Attack, Avoid, Survive: Essential Principles of Self Defence

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Crash Combat Second Edition with additional content.
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