for what purpose, in the development of a new rifle/carbine, or rather a barrel / cartridge assembly, in addition to tests of barrels of standard length, very short barrels were also made [for the same cartridge]?
For example: barrel length ~ 12cm = end of barrel in bullet positon (for ex. size of cartridge 12,7x99).
Maybe for the primer tests? Shooting to white paper and pollution assessment?
Or as on photo below - .22 flame size measurement, strenght of the primer.
But for this two types of test probably useds only a cut / shortened cases [not full size chamber].