Identification Needed for Unknown Aerial Type Bomb

[inertordnance]

Inert unknown aerial type bomb. Measures approximately 24 3/4 inches overall length with fuze attached and 22 1/4 inches without fuze. Body is 3 1/2 inches in diameter and fins span 4 1/2 inches in diameter.

Body is machined steel and tail fin assembly is sheet metal, attached to the body with screws. Color is flat yellow and appears to be vintage.

Body is marked overall: BS CO. - LOT NO. 2410 - BI4 - BOOST M.1 - K825

Fuze is marked: C

Photos attached for additional details.

Any information related to country, era, nomenclature and any reference material would be greatly appreciated.

Thanks and stay safe,

Frank

 

[Slick]

The fuze has a French air about it.
That's all I got.

 

[Yodamaster]

BS Co : (US) Bethlehem Steel Corporation

During WWI and between the two WW, USA manufactured a great lot of bombs on French drawings, first to helped the French aviation and to armed his own Air Force.
This bomb and this fuze are effectively of French design. Badly, I don't find them in my books.


Yoda


Yoda

 

[Dreamk]

It looks indeed as a US 17lb Frag MkII from the early 1920s, itself a development (almost identical) of the French "obus de 75mm Michelin" bomb of ww1.

Here are drawings of the US 17lb MkIIOB on the Left and of Michelin bombs on the right (the 75mm is the second, lower, from the left):


However there are 3 important variations on this bomb that make it different from the regular model:

1) the rear part of the fins is angled so as to give a rotation spin impetus during fall
(I must say that it's the first time I've ever seen a spinning feature on a US bomb model).

2) Its diameter is wider by 15% than the regular model's (3.5 in instead of 3 in) (Length is compatible with the official data)
This probably reflects the facts that these bombs were generally made by using reconverted artillery shells - the original ones using a 75mm shell, this one a 88mm shell or more probably a reworked, grounded 90mm shell (I don't think the US artillery ever used 88mm guns, but the 90mm was a "ww1 French classic" together with the 75mm).
It is worthy to note that the French produced in 1917-18, for the American Expeditionary Forces, 10kg Type P bombs based on reworked 90mm artilley shells (drawing from Deminest).


3) the fuze - generally these bombs had a characteristic fuze extension

The fuze seems to be similar to this one used on French bombs for training during the 1918-1930 period:



Asd a matter of fact this fuze was indeed originally a fuze used on 75mm artillery shells:



This is what I've got on the 17lb Frag MkII:

 

[HAZORD]

It looks like a U.S. produced Russian 76.2mm artillery projo converted to bomb.

 

[Dreamk]

The French and the Soviet used in the interwar period to systematically re-use discarded Artillery Shells as bodies for Aircraft Frag Bombs - The Soviet AO8 M3, M4 & M6 (76.2mm shells) , the Soviet FAB 50 M4, M5, M6 & M9 (152mm shells), FAB 50 M8 & TR (155mm shell) the French 10kg type P, 50kg type A, etc...

 

[MINENAZ16]

Hello,
Nice US 17lb but the fuze is not correct.
French 24-31 RY M1917 for artillery or mortar projectiles. Need inertia to be armed so can not work on bombs.

 

[inertordnance]

Gentleman,

Thanks Much for the valuable input!

Stay Safe,

Frank