M71 - Blue under OD paint

[Dunkbfg]

Picture below of 1945 90MM M71 HE shell - recently acquired.

Any idea why there would be blue paint under the OD paint? I'd guess a dummy with inert fill changed to active.......... Lettering looks like it was added after WW2, possibly Korea (not sure why I think that! - maybe because of the yellow painted lot number which I've not seen before).

Also, can anyone explain what the difference is between a straight TNT load and the TNT with supplementary charge?

Many thanks for looking and any help.

Duncan.

 

[Spaceinvader]

My guess for the paint would be someone bought it as the blue training round, then re-painted t as an HE round.

 

[US-Subs]

I think instead that either the government ran short of bodies and recycled practice rounds, repainting the blue to OD, or the blue is some sort of primer. I've got two more with blue paint showing through, and all are correct period OD and markings. One of mine came out of St. Louis, the other from Massachusetts.

 

[flak18]

Fuzes with a small gaine...like the WW2 standard PD M48 did not intrude very far into the TNT filling in the projectile. However, with the introduction of Proximity fuzes a much deeper cavity was needed in the TNT, the Proximity fuze being a much longer fuze. So, to overcome the problem, a standard deep cavity was left in the TNT when filling to accomodate the Prox fuzes. Then, to cater to the other shorter fuzes, a removeable supp charge was placed in the cavity...if firing M48 supp charge left in, if firing Proximity supp charge removed.