The Mk 45 Mod 4A Medium Calibre Gun on HMS Glasgow, the first Type 26 frigate, is capable of firing 5-inch shells weighing up to 31.5 kg at speeds between 1,841 and 2,351 mph—up to Mach 3, or three times the speed of sound.

With an effective range of up to 37 km (20 nautical miles), the Mk 45 Mod 4A is not just about power but precision.

The system can be used for traditional naval gunfire support, pummelling enemy positions ashore, and is also equipped to handle fast-moving inshore attack craft and aerial threats, including drones.

One of the most remarkable features of the Mk 45 Mod 4A is its fully automated ammunition handling system. Traditionally, sailors were required to manually form a chain to load shells into the gun, a labour-intensive and potentially dangerous process.

The new system, however, automates this task, drawing on technology first used in the US Navy’s Zumwalt-class destroyers. It ensures a continuous supply of shells from the ship’s deep magazine to the gun’s 20-round ready-to-use magazine, significantly reducing the crew’s workload.

Click to enlarge.

This automated system also enhances reliability, with other navies reporting that the Mk 45 Mod 4A achieves a 99.6% availability rate. In the event of a failure in the automatic system, the gun can still be manually reloaded, ensuring its operational capabilities are maintained even in extreme conditions. The absence of manual handling also makes the system safer for the crew, as there’s no need to lift heavy shells or work around moving machinery, which reduces the risk of injury from the noise and vibrations caused by the gun’s firing.

In terms of firepower, the Mk 45 Mod 4A can fire at a rate of up to 20 rounds per minute, offering sustained firepower in high-intensity combat scenarios. The gun can operate in two modes: Mode III for sustained operations, which requires a six-person crew, and Mode IV for automatic operations, where the gun can fire 20 rounds without the need for personnel inside the mount.

The design of the Mk 45 Mod 4A also includes a longer barrel than its predecessors, which allows for more complete propellant combustion, increasing the velocity and range of the projectiles. This makes the gun particularly effective for land-attack missions, where precision and range are critical. Additionally, the system’s radar signature has been reduced thanks to a modified flat-panel gun turret, making it harder for enemy forces to detect.

HMS Glasgow is the first of eight City-class frigates set to replace the Royal Navy’s ageing Type 23 fleet.

According to Neil Stevenson, Type 26 Weapons Group Leader at Defence Equipment and Support, “The Mk 45 Mod 4 is a proven, effective weapon that incorporates the latest technologies for today’s multi-mission warships.”

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George has a degree in Cyber Security from Glasgow Caledonian University and has a keen interest in naval and cyber security matters and has appeared on national radio and television to discuss current events. George is on Twitter at @geoallison
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Finney
Finney (@guest_852225)
22 days ago

The gunhouse looks less stealthy than that on the 4.5’s, I don’t suppose it makes a huge amount of difference but might be a nice project for a UK firm to design a better one and then try and sell it on for retrofit to the large 5″ user-base.

Michael Loughlin
Michael Loughlin (@guest_852242)
22 days ago

Question.. will this make a sonic boom ?

AlexS
AlexS (@guest_852259)
22 days ago

UKDJ is better than this tittle.

Daniele Mandelli
Daniele Mandelli (@guest_852398)
21 days ago
Reply to  AlexS

Is that a misspell or you meant to describe it as Tittle?

AlexS
AlexS (@guest_852399)
21 days ago

🙂 misspell. This is a tabloid title is what i meant.

Daniele Mandelli
Daniele Mandelli (@guest_852412)
21 days ago
Reply to  AlexS

You could have meant either! Describing something as “tittle” is also a thing. 😆

George
George (@guest_852687)
21 days ago
Reply to  AlexS

I think I preferred the misspelling with copious amounts of tattle. Describes UKDJ perfectly.

AlexS
AlexS (@guest_852792)
20 days ago
Reply to  George

Buh!

Bradley
Bradley (@guest_852325)
22 days ago

Is it standard to have no rear defence? If an enemy sub pops up behind doesn’t look like there’s much it can do?

AlexS
AlexS (@guest_852413)
21 days ago
Reply to  Bradley

That is a criticism that i also make.. It has 2 30mm guns in hangar corners but those are not CIWS grade.

Dern
Dern (@guest_852567)
21 days ago
Reply to  Bradley

What do you define as rear defence? CAMM and Mk41 certainly can fire into rearward arcs. Plus decoys generally get left behind when fired so end up behind the ship….

Bradley
Bradley (@guest_852658)
21 days ago
Reply to  Dern

Yes you are right I read further on the subject and the necessity of rear cannons has been reduced due to missile capabilities over the years.

David Craig Stevens
David Craig Stevens (@guest_852340)
22 days ago

The RN River Class based on the type 26 is using the Italian 127mm,I wonder if the rounds are interchangeable.Nice way to lay a D Flag in WW2 with a “broadside”.

David Craig Stevens
David Craig Stevens (@guest_852341)
22 days ago

Sorry RCN River Class.

David Craig Stevens
David Craig Stevens (@guest_852342)
22 days ago

The “old man” would look real stupid down the road when ya slip in for a RSH and his 5″ Italian rds don’t fit your guns doi???

David Craig Stevens
David Craig Stevens (@guest_852344)
22 days ago

Or vice versa.

David Craig Stevens
David Craig Stevens (@guest_852347)
22 days ago

I wonder if NATO 5″rds are all Interchangable?A german 127mm just as good?Mix and match?Maybe a rebored ww2 128mm to russian 130mm would blow thier minds or sticking some 128mm ww2 piece of natzie crap into a 127mm.I bet those German 127mm guns probably can fire thier ww2 128mm ordinance.

David Craig Stevens
David Craig Stevens (@guest_852348)
22 days ago

Remember that next time you need “babyfood” in crippelgate.Im on D for dentist forgive my ignorance.

AlexS
AlexS (@guest_852403)
21 days ago

Germans use Italian Leonardo guns. There was last year in Naval News an article that German Navy accepted their long range Vulcano rounds in service.
In Western world there are basically 2 naval gun industries Leonardo(127, 76,40, 30,25 etc) and BAE(after it bought the Bofors with 40 and 57 and US 127 manufacturer)

Last edited 21 days ago by AlexS
AlexS
AlexS (@guest_852409)
21 days ago
Reply to  AlexS

There are smaller ones, but these 2 are the only ones that have 127 mm offers and have a full range.

Dern
Dern (@guest_852568)
21 days ago

In theory all NATO rounds are interchangeable. Eg a British Sharshooter rifle in theory can fire American M240 ammunition.

In practice this is very rarely the case, as propellant charges and quality are variable enough from nation to nation that you’d only risk it if you where truly desperate. (You try an put M240 ammo through a L129, even though they’re both 7.62×51 you’ll find yourself having constant stoppages).

For 127/5′ it’s an open question, I think you’ll fire a round. What happens after? I’m not sure it’s been tried.

Last edited 21 days ago by Dern
David Craig Stevens
David Craig Stevens (@guest_852593)
21 days ago
Reply to  Dern

Funny,in ww2 the British 9mm sten ammo wasn’t interchangeable with the german 9mm parrabellam,so what’s changed?The Russian AKs are 7.62mm will thier ammo work in our nato 7.62mm?

David Craig Stevens
David Craig Stevens (@guest_852599)
21 days ago

What happens these days with all the high teck electronics?Is an Italian 127mm going to be able to interface with a RN 127mm?What happened in Hong Kong in the 1990s?The RN just toss half thier ordinance because of Hong Kong being O 8?All thier ammo made in Hong Kong by Chinese subcontractors?Something to ponder when filling up your bastions with ordinance.Ask a RN Ordanance Officer if they would permit an Italian 127mm Evan be fired by a RN “Ship O the Line”?

Dern
Dern (@guest_852673)
21 days ago

What on earth is this even supposed to mean? Why would a Leonardo 127 “interface” (what’s that even supposed to mean in this context!?) with a BAe 5′?

Dern
Dern (@guest_852636)
21 days ago

Russian 7.62 will not work with our 7.62 the Russian calibre is 7.62x39mm, while NATO uses 7.62x51mm. They won’t even fit in the respective chambers.

And nothings changed. The Sten was specifically designed to accept German made 9x19mm parabellum.

David Craig Stevens
David Craig Stevens (@guest_852655)
21 days ago
Reply to  Dern

Well that’s interesting because sten gun ammo won’t fit in a 9mm Walther ppk or lugar or schmiesser.

Dern
Dern (@guest_852672)
21 days ago

I mean it will fit, at least in an MP40, and in later Lugers (the original Lugers where chambered in 7.62×21 so yeah sten ammo won’t fit in those). Probably wouldn’t try to fit it into a Walther PP since those aren’t chambered in 9x19mm at all (they’re 9×18 or 9×17 in the closest configurations).

How reliably a MP40 will fire Sten Ammo is a completely separate question, I’d suspect you’ll get a lot of stoppages.

Last edited 21 days ago by Dern
David Craig Stevens
David Craig Stevens (@guest_852679)
21 days ago
Reply to  Dern

I suggest that like you originally stated the configurations in nato interchangeable ordinance could be an asimilar problem in future conflicts.What happens if ammunition has classifications as being compatible but then isn’t?If the RN and RCN want to use different 5″127mm guns on thier respective new classes then they should make sure thier ammunition are compatible for thier standard ordinances,as well as being interchangeable .The same applies to USN 5″ and German 127mm.

Dern
Dern (@guest_852688)
21 days ago

Holy fuck you need to work on your communication skills because that’s illegible.

David Craig Stevens
David Craig Stevens (@guest_852692)
21 days ago
Reply to  Dern

Well precise would mean to sum it up:make sure your ammunition you use works properly in the gun you use it in before you use it.

Dern
Dern (@guest_852789)
20 days ago

We do.

DJ
DJ (@guest_852350)
22 days ago

I understand this gun can also fire Leonardo’s volcano round (range to 80km).

AlexS
AlexS (@guest_852411)
21 days ago
Reply to  DJ

There have been some news long a go of collaboration between Leonardo and BAE to offer Vulcano rounds in MK45 but no recent news on that.

ChariotRider
ChariotRider (@guest_852441)
21 days ago

I was just thinking we haven’t much more about the possibility of Norway buying the T26. I did a quick look via google and the last article was in early May, I suppose that is only a few months ago and these things take awhile. However, the thing that occurred to me is that if the Royal Norwegian Navy (RNN) did buy 5x T26 (or even if they only bought 3!) the Royal Navy’s ships would be delayed but it could turn out to be an advantage given that austerity is set to continue. If the RNN could take over… Read more »

Paul T
Paul T (@guest_852589)
21 days ago
Reply to  ChariotRider

There are a lot of New Frigate programmes underway in Europe currently, it would be a major success if the Norwegian Govt chose the Type 26.

Frank62
Frank62 (@guest_852524)
21 days ago

Pity we didn’t select this for all future escorts as the sole medium gun across the fleet, as it’s wasted on our most expensive, least dispensable frigates. Should be on the T31s.
At least after glacial building we’re finaly getting a T26 closer to delivery.

AlexS
AlexS (@guest_852545)
21 days ago
Reply to  Frank62

Agreed this should be in T31, the 57mm should be in the T45 and T26

Nick
Nick (@guest_853083)
19 days ago

“With an effective range of up to 37 km (20 nautical miles), the Mk 45 Mod 4A is not just about power but precision.”// “In terms of firepower, the Mk 45 Mod 4A can fire at a rate of up to 20 rounds per minute”     My understanding the 20 nm range quoted is its maximum theoretical range firing with barrel at 47 degrees using the EX-175 high energy 26 lbs propellant charge burning the barrel out at a much faster rate,1,500 rounds?, than the standard Mk.67 18.25 lbs charge which has barrel life of ~7,000 rounds and rpm would drop to 10 with… Read more »

Tommo
Tommo (@guest_853536)
18 days ago

What about emergency resupply if power to the hoists is lost And FOST staff want it tested in drills a 4.5 Tanked Rd is just over 84lb including its tank ,one on your shoulder was a pain 5inch shell and cordite is what weight?