help id 116mm length swiss cased round

[womble]

Hi all I hope everyone is keeping safe, please see pics of a round and case I have- the case length is 116mm and the proj appears to be 26mm (not 25mm and not 27mm), I have looked through most of my books/info etc and after internet searching I seem to have drawn a blank, so if anyone can provide any info then that would be appreciated.

Thanks in advance

Cheers

Womble

 

[earni74]

Hi Mike, i have it in my book as a Swiss 25x116mm R31.8mm unknown experimental Machine gun, Circa 1960
Mick

 

[womble]

Mick

Thank you for the quick reply,at first I thought it was a 25mm but the proj front wise would not go into a 137 KBA case so assumed it was 26mm, I know you should always get the gauges out and not make assumptions- it must have been extremely tight in the bore.

Cheers

Womble- Mike

 

[earni74]

No problem, the swiss had a service round in 24mm, its a bit strange they would develope a 25mm round, a line drawing in the De Hek book shows a 25x116 belted dummy
Mick

 

[Tony Williams]

At first I assumed that you were talking about the 25 x 116B aircraft gun round, but yours doesn't have a belt and I know nothing about it other than the brief note in Hawkinson.

Anyway, in case anyone is interested this is my entry for the 25 x 116B in my forthcoming book:

This interesting cartridge was offered in the early 1960s in one version of the Oerlikon 251 RK aircraft revolver cannon (the others being in 20 x 128 and 30 x 113B). It basically used the 30 x 113B case necked-down to 25 mm, with the overall round length kept the same at 199 mm. This was potentially the best overall compromise for an aircraft gun of the period, combining a muzzle velocity comparable to 20 mm rounds with a significantly greater destructive effect, but the timing was wrong – NATO nations were by then committed to the 30 mm ADEN/DEFA or the 20 mm M39 or M61. Weight of the dummy round shown is 300 g (at a rough guesstimate the service round would have weighed c.380 g). The 165 g HE projectile was designed to contain 32 g HE and was fired at 1,040 m/s.

 

[womble]

Mick and Tony

Thank you for your posts, Mick I had seen the 25x 116B in the copy of the book by De Hek that I have, but there is no mention of this round,I had also checked through all the books I have by Tony. I appreciate that there may not be much know about this round but would it have been developed for aircraft or ground use or both, if it was for aircraft then Tony if you wish I could bring it to the next ECRA meeting if you want to take your own photo if you want to include it in your forthcoming book- just send me a PM.

cheers

Womble

 

[Tony Williams]

Thanks very much Mike, I would appreciate that (assuming we are allowed to travel by then...).

I have a Swiss friend who specialises in Swiss cannon ammo, so I'll drop him a line.

 

[womble]

Tony thank you for your post,no problems, hopefully there will be the November meeting at Bisley.

cheers

Womble

 

[Tony Williams]

I now have a definite identification of your 25 x 116 round. It was intended as an option for users of the Oerlikon 204 GK AFV gun (which as standard came in 20 x 128 calibre). It was created in the late 1950s - early 60s simply by shortening the 20 x 128 case and necking it out to 25 mm (the overall length of the round was the same as the 20 x 128). No-one bought it and it is a very rare beastie - even my Swiss friend does not have one!

One curiosity I noticed when comparing measurements is that the case body diameter of the 25 x 116 is identical to that of the 25 x 116B I posted about earlier in this thread. Basically, it is effectively a 25 x 116B with the belt turned off. That means that it (and therefore the 20 x 128) also has the same body diameter as the 20 x 135 Mauser MG 213C revolver cannon round. Possibly not a coincidence?