Girovagando in rete ho trovato questi proiettili, se ho capito bene dicono che sono Russi ma non mi pare che parlino di prova forzata....
https://forum.cartridgecollectors.org/t ... 1/31311/13
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Ha scritto dopo 5 ore 48 minuti 5 secondi:
Avevo chiesto lumi all'autore e mi risponde cosi..
The bullet has a hollow tail, which allows the firing gas to fill in and expands the tail.
This makes the bullet stick harder against the barrel in order to increase the firing pressure in barrel when the weapon is fired.
There are 3 little holes around the bullet evenly. They are about to make the former jacket stronger than the hole tail part. In this case only the tail can be expanded to increase the pressure, not the hole bullet.
In addition , these 3 holes can make the head part of the bullet stronger, so that it wouldn’t break in the barrel when firing.
And it has nothing to do with the case to increase the firing pressure.
Hope my answer help you to understand it.
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Se ho capito bene i tre fori servono acchè l'ogiva si riempia di gas che dilatando la parte inferiore dell'ogiva stessa fanno si che la tenuta, e quindi la pressione, siano superiori alla media.