The odd 7.62x39 blank


#1

Gentlemen,
One English seller offers the unusual 7.62х39 blank cartridge.
http://www.specialistauctions.com/auctiondetails.php?id=1523422
The any additional information on this cartridge interests me. I assume that this cartridge is made for use in the British cinema.
But with pleasure I will listen to any your assumptions.


#2

Firstly, what are the dimensions? Is it a “Replica”(Fake) made directly from a 7,9mm case, retaining original dimensions, or is it a “swaged down” case, to the smaller .444 head diameter ( and turned down rim and new extractor groove)

The “extended Bullet” design is typical of the uncrimped RCBS 7,62x39 Forming set…also of the same type of 7,9x33 taper closure (still requries a card or wax wad).

Without dimensions to confirm a “Fake” or a proper Blank, I can’t make any further judgement.

BY the way, “oil injected” primer deactivation is NOT a safe means of deactivating Primers…they can (and often do) still ignite.

Only actually firing it,( Hot Plate) or soaking in warm vinegar,(24 hrs) will deactivate the priming composition.

Unreliable method of closing blanks, both for feeding problems in some guns, and also wads can fall out (and powder) under vibration of rapid fire.

Star crimp is the best way, followed by the taper to form up the point properly.

Regards,
Doc AV
AV Ballistics Film Ordnance Services
AV Blankfire Pty.Ltd.
Brisbane Australia.


#3

DocAV,
I know that this nonindustrial production. I have understood that it is reload from 7.92х57 cases. But, on the other hand, this cartridge has an original design. Such design demands creation of the original tool for case formation. It will not be simple person to make the original tool for production of blanks. The basic consumers of blanks are army and cinematographers. But the army has no problems with shortage of cartridges, and cinematographers have. Therefore they are forced to search for the problem resolution. And the cheapest the decision. I have some cartridges adapted on film studios. I hope that sometime I will have this cartridge. Then I can measure it. Now I have no this cartridge and consequently I ask questions here


#4

Dear 2moutrage,
As I mentioned above, the Tool (Die) for making this particular profile is manufactured by the USA Company RCBS Reloading Tools. It is readily available to Reloaders and People in the Cinema Armoury Business.

The proper Parent Case for a 7,62x39 Blank is the Italian 6,5x52 Carcano case (Correct Body diameter) and NOT the 7,9mm case, which is .025" greater (0.64mm) in diameter than a 7,62x39 case.

Thus a 7,9 case also required the head diameter reduced by sizing in a couple of step-down diameter dies, before it can be formed into a 7,62x39 Blank case. These step down dies are also available through the USA specialized reloading Market (CH4D and RCBS Specialty Dies.)

Dear Sir, I understand English is NOT your first Language, but do you speak some other European Language ( French, German, Spanish etc) and our conversations may bne more easily understood. MY Eastern European and Russian Knowledge is very minimal…

Regards,
Doc AV
AV Ballistics.


#5

You are right, it is easier to hear the answer to a question there where less pathos and where speak in a native language.
Bye!