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  1. #1
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    27 mm Experimental

    In 1947 General Electric, under the name "Project Vulcan", began the development of the modern , externally powered gatling gun.

    The first 10 guns delivered were the Model T45 in 60 cal (15.2 x 114).

    Further work produced a second batch of guns (33 in total), Models T45, T171 and T150.

    The T45 was , again, in 60 cal.

    The T171 was in 20 x 102, based on the 15.2 x 114 case. The model was developed into the M61 Vulcan.

    The T150 was in 27mm and was again based on the 14.2 x 114.

    Chinn (Vol III) lists overall length of all three rounds as 6 5/8 inches. The 27mm was listed by Chinn with a mv of 3300 fps.

    The T151 was a revolver canon developed by the US also in 27mm, but this was a relatively low velocity round (2000 fps).

    Has anybody have a drawing or picture of this round.

    Chinn NEVER put pictures or drawing in his books.




  2. #2
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    Hi see post 4 on this thread. Its a T 142 but the overall measurements match the round you mention.
    http://www.bocn.co.uk/vbforum/thread...winchester+t45

    There is one for sale at the moment on classifieds (the photograph of the one for sale shows the dummy fuze partly unscrewed)
    http://www.bocn.co.uk/classifieds/sh...rimental&cat=3

    Dave.
    Last edited by SG500; 18th January 2016 at 07:05 AM.

  3. #3
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    Last edited by bdgreen; 18th January 2016 at 08:25 AM.

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  5. #5
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    Quote Originally Posted by Big Al View Post

    The T150 was in 27mm and was again based on the 15.2 x 114.

    Chinn (Vol III) lists overall length of all three rounds as 6 5/8 inches. The 27mm was listed by Chinn with a mv of 3300 fps.

    The T151 was a revolver canon developed by the US also in 27mm, but this was a relatively low velocity round (2000 fps).
    The 3,300 fps figure is way out.

    There were two different 27mm rounds developed for use in the T150/151 cannon: the 27 x 70B fired a 250 g pro at 610 m/s (2,000 fps) and the 27 x 97B (the same case, lengthened) fired a 200 g proj at 840 m/s (2,756 fps).

  6. #6
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    According to Chinn (Vol III, page 93) the 20 mm round has a velocity of 2000 fps (T171 gun) and the 27 mm has a velocity of 3300 fps (T150 gun). This is obviously in error. The column headers were probably switched.

    Based on your information Tony, I would guess that the T150 used the 27 x 97B round.

    Thanks everyone for the help.

  7. #7
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    As far as I know the 27x70Bmm rounds were developed by Olin Mathieson, East Alton, Illinois. Several variations were made (HEI (T144), Target Practice (T142), Dummy (T143) and High Pressure Test), but in relatively small quantities. One pilot lot of about 50,000 rounds of the HEI were made for testing. I do not know when the contract began, but it was supposedly sponsored by the Army Ordnance Corps and terminated in 1955. Even though the Ordnance Corps sponsored it, I have always heard it was for an airborne gun system. The projectile length for the HEI was 113mm and it weighed 250 grams with the fuze. Velocity was given as 615 m/s (2,000fps). I have never seen a photo, or a round, of the actual fuzed HEI cartridge. The electric primed cases for the rounds were made in both brass and aluminum. There was also a long cased version with a shorter projectile. This round was the same overall length as the 70mm case lengthed round. It had a 96mm long case. a velocity of 860m/s (2,700-2,800 fps) and a projectile that weighed 200 g with fuze. I have never seen an example of the long cased version. 27mm rounds.jpgThe photo from my collection shows from left to right a T143 Dummy, aluminum case and a blue band around the projectile (purpose unknown); a variation in case finish of the T143 and an unpainted projectile; a brass cased T142 Practice round; an aluminum cased T142 Practice round with the base of the case apparently dipped in black paint. You can also note the various case crimps used on the rounds.

  8. The Following 2 Users Say Thank You to EODGUY For This Useful Post:

    bdgreen (21st January 2016), SG500 (21st January 2016)

  9. #8
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    Yes, these rounds were for aircraft guns. The idea was to achieve the greatest destructive effect possible within the same overall cartridge size envelope as the 20 x 102, so that 20mm gun designs could be easily adapted to the larger calibre.

 

 

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