Unknown gun/mounting model

[Jaisheelal400]

I'd have named this better if I had any certain idea what it was
I purchased the model a year ago, presented in a large and well-made box marked "MOD". It came with a small note saying that it originally belonged to a man who worked at R.O.F. Nottingham, and whose son then sold the thing at auction.
It's a very heavily-built and very well-finished - if somewhat sparingly detailed - model, and looks to be from perhaps the 1960s or 1970s (although I'm no expert at dating this sort of thing.)
The trunk (if the door on side is any suggestion) would be the height of a full deck, and there is absolutely no way that this thing would fit in any sort of reasonable land vehicle.
The barrel is rather skinny for its length by naval standards, and has a bore evacuator (which I've only seen in naval guns on the 4.5-inch Mark 8, famously derived from the R.O. L7)
Consequently, my theory from the very beginning was that if it was anything, then it was some attempt to navalise the gun from a tank/SPG, and Hood suggested to me in private correspondence that it might be something to do with Marconi's 105mm "Autonomous Patrol Gun" project (also based on the R.O. L7 but without upscaling the gun/ammunition), intended for use on offshore patrol vessels.

I'm taking it all with a pinch of salt, because it might simply be some sort of practice job for honing the model-making skills of the builder, or a comedically-exaggerated example for instructional purposes.

I would very much welcome any input, and I apologise in advance to the moderation team if this is in the wrong place.

A photograph of it in the shop:

And a photograph I took today, albeit in rather unflattering light:

 

[Tony Williams]

You are correct in your analysis. It is a model of the 105mm Naval Patrol Gun MkI. I have a photocopy of a brochure from RoF Nottingham dated July 1981. It used the same ammo range as the NATO L7 tank gun.

If you (or anyone else) is interested, I can rev up my scanner and post the thing here - it runs to 6 pages.

 

[Hood]

I'd be interested in seeing the brochure.

This little gun has been popping up for years in these forums and we've never seen the thing until now.

 

[Jaisheelal400]

If you (or anyone else) is interested, I can rev up my scanner and post the thing here - it runs to 6 pages.

I definitely would be.
Although I'd never heard of this particular project (instead having surmised essentially the same story from its features), I did come across this whilst looking.


https://themarconifamily.pbworks.com/w/file/fetch/132466005/Radar Systems International No.27.pdf (from this)

 

[Hood]

Can't add much other than this out of Jane's Weapon Systems.

 

[Tony Williams]

Here we go:

 

[Jaisheelal400]

Excellent, thank you very much!
I'll be honest, I never expected such a hasty resolution. No doubt remains in my mind that it's the exact same system
This does appear to be a different - and perhaps somewhat larger - model (porthole on the hatch on the turret, no visible periscope, etc...) but absolutely depicting the same thing
Very satisfying to know at last for sure

 

[TomS]

Here we go:

Couple of interesting things sort of buried in the text here.

1) Reference to a possible assisted loading system, only in the spec sheet under "Rate of fire" and not, as far as I can tell, mentioned anywhere else.

2) Proposal for separate loaded HE and Starshell rounds with a "newly developed charge system." Do you suppose that the projectiles would be Abbot/Light Gun 105mm shells with some sort of separate cased charge sized to fit the L7? Or something else?

 

[Tony Williams]

2) Proposal for separate loaded HE and Starshell rounds with a "newly developed charge system." Do you suppose that the projectiles would be Abbot/Light Gun 105mm shells with some sort of separate cased charge sized to fit the L7? Or something else?

Sorry, I know very little about such large-calibre projectiles.

 

[kqcke for you]

Its a little Like Monarc tought Monarc was a 155mm from PzH 2k

 

[TinWing]

A possible motivation for the naval 105mm L7 might have been the fear that an OTO 76mm wouldn’t puncture the pressure hull of many modern double hulled Soviet submarines. You could damage a hostile sub and force them to the surface but potentially could’t sink them. Or at least that was the fear, which as much as shore bombardment in the Falklands motivated the replacement of the Italian 76mm with the domestic 4.5” Mark 8 on the Type 23. I’d also suspect that the Italian gun was considered to be expensive by the RN and conserving foreign exchange was a consideration. D.K. Brown was a great proponent of the 105mm L7 for the Castle Class but claimed that increasing the elevation of the mounting blew up development costs and put paid to the entire project. That would support the conjecture that the original purpose was direct line-of-sight fire at the pressure hulls of Soviet submarine. Not as difficult a task in hitting one as one might think since Soviets subs had more reserve buoyancy than their single hulled western counterparts and rode higher in the water.