Both have the same headstamp “aym 53”. Why such a difference between them?
Above. dummy for Sa 24 and 26 submachine guns (7,62-Pi-Šk-24,26).
Below: dummy for vz. 52 pistol (7,62-Pi-Šk-52).
Why is the difference in shoulder and overall cartridge length? Are pistol and SMG chambers different?
The SMG has a blow back breech system. The breech feeding the cartridge would ram the case into the chamber (as it would take all energy of the moving breech) and make the case neck/shoulder “flow” and being pushed back to the pos. you see on the shorter type. This way the then “longer” neck could lodge in the chamber of the SMG and make extraction difficult. To prevent all this the shorter case was made.
There are actually 3 variations; long neck/long shoulder, long neck/short shoulder, and short neck/short shoulder.
May you post a comparison photo of all 3 types?
This reminded me of a discussion on Fórum GunShop.cz I ran across recently concerning 7.62x25mm Tokarev, a couple of postings appear to discuss the use of a heavier bullet in the early 1950’s Czech MG loadings versus pistol loadings: http://forum.gunshop.cz/vlastnosti-streliva-7-62x25-tokarev-t4936-30.html
I had to use an online translator which of course resulted in a minimal understanding of the forum discussion on my part so can anyone provide any additional information concerning the “heavy ball versus light ball” bullet loadings?
How could these both be considered variations of a “x25mm” cartridge when they are clearly not both 25mm length?
Because the shorter variant was also made for submachine guns chambered for the 7.62x25 cartridge, as there aren’t 7.62x23 loaded cartridges or chambers having these dimensions. A shorter case and lower shoulder position permits the bolt to close a gap of 2 mm that ocurs when a normal cartridge is loaded, and thus avoiding a deformation of the case.
Apoc, I think it must be observed what the normal chamber is made for.
Means there are calibers which are using shorter cases than designated for special loads and some are using longer ones. These will still be designated with the original caliber designation. There are plenty of such examples.
A good example is the 40x46SR case for the grenade launchers (M79, M203 and about 100 more models).
There for example US illum loads do use a 30mm long case and German irritant loads for anti riot purposes do have 123mm long cases. I think there are at least 20 more case lengths available in 40x46SR.
So caliber designation of these cases is still 40x46SR while the case measurements are different and do not pose a new caliber.
My joke fell flat. Or was poorly phrased. My intent was to poke fun at how “European” designations are usually comparatively precise where “American” is less so (44 Magnum being .429, etc).