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Thread: 25 x 181

  1. #1
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    25 x 181

    Hi all please see pic of a 25 x 181 round I have, below it is a 25 x 184 for comparison, any info or comments would be appreciated.

    thanks in advance

    Cheers

    Womble





    25x 181 ex.jpg

  2. #2
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    The measurements of the KBB round have been the subject of much confusion. It was for a long time known as the 25 x 184, but no round with these dimensions ever entered production as far as I am aware (although I suppose it could have featured in the development stage).

    This cartridge ended up with two different case lengths for different loadings, as explained below (more of my book extracts!)

    25 x 173/181 Oerlikon KBB

    The 25 x 137's big brother, developed from 1966, uses a lengthened version of the same case in two versions with different neck lengths: 181 mm with Anti-Missile Discarding Sabot (AMDS) and other discarding sabot rounds, and 173 mm for full-calibre TP-T and HE loadings (see photo below). To complicate matters further, this round was for a long time commonly referred to as the 25 x 184; presumably the result of an early error being copied.

    KBB-6 copy 3.jpg
    Overall round length is 288 mm and weight is 620 g. Combat loadings are:

    HEI SD: 230 g hardened steel shell with ballistic cap, contains 20 g Hexal plus incendiary mix; base fuze with self-destruct function; MV 1,160 m/s.

    APDS-T: 190 g projectile with 14.5 mm diameter, 156 g tungsten alloy penetrator in a plastic/light alloy sabot; MV 1,285 m/s; penetrates 34mm/60°/1,000m (also AMDS without tracer, and FAPDS; same ballistics).

    Although the KBD rotary cannon was developed to fire it, the only service use is in the Oerlikon KBB single-chamber gun, which itself has only been used in a naval CIWS which was purchased only by Turkey. Although it remains in service, it is being gradually replaced and it seems unlikely to enjoy a long future. The ammunition is no longer advertised.

  3. #3
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    Tony thank you for your post and info, the one bottom in my pic is 3mm longer (184) case wise than the top one (181) - it has a slightly longer neck which as per the pic makes the overall round 3mm longer.

    Many thanks again

    Cheers

    Womble

  4. #4
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    Interesting - I can only assume that it was a development round.

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    Womble, is the date headstamped?

  6. #6
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    Tony thank you for your post, the headstamps are 181 case 031 84 PSW in a circle 184mm 002 96 BM.

    Cheers

    Womble

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    Headstamps aren't really my thing, but IIRC that seems to suggest that the 184 mm case was made in 1996 by BMARC. Which is weird!

  8. #8
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    BM was indeed a monogram of the British Manufacturing and Research Company (an interesting company). Originally founded as a shadow company for Hispano-Suiza in 1937 and they remained the parent company until 1971. During this period their monogram was BMARC and BMRC GM. In 1971 the parent company was Oerlikon-Bührle who retained ownership until 1988 and the monogram for this period was BM. In 1988 the company was sold to Astra Holdings to become Astra Defence Holdings and the monogram changed to BMO. However, although sold to Astra there were still Oerlikon contracts being executed. In 1992 Astra Defence Holdings went into receivership and what was BMARC was bought by British Aerospace. The Grantham site was sold in 1994. The 2013 ESTC list of manufacturers' monograms still shows BMO as Astra Defence Holdings, although non-extant, details required for possible stocks still retained

    TimG
    Last edited by TimG; 26th April 2020 at 11:08 PM.

  9. The Following User Says Thank You to TimG For This Useful Post:

    Tony Williams (27th April 2020)

  10. #9
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    Thanks Tim, a useful summary.

  11. #10
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    Tony and TimG thank you for yours posts.

    Cheers

    Womble

 

 
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