Quote:
The .25 acp was likely designed with the unreliability of rimfire ammo in mind... If offers similar ballistics to the .22 lr while being reloadable.
|
Actually, IIRC another primary factor was that the .25ACP cartridge was designed around the turn of the 20th century when black powder .22LR ammo was still commonplace.
Since .22LR uses a heeled bullet- i.e. the body of the bullet is the same diameter as the case- the bullet must be shoved through the powder residue left by the previous shot; consequently, black powder .22LR basically won't work in semi-automatic firearms because the powder leaves so much residue behind that subsequent rounds won't chamber. The shooter would have to cease firing and clean the gun after only a handful of shots.
It's obvious why this wouldn't work in a defensive firearm.
This is also the reason that Winchester's first semi-auto rifle, the Model 1903, used a proprietary rimfire round with comparable ballistics to .22LR- the .22 Winchester Automatic. This round was exclusively loaded with smokeless powder to ensure that the gun would function reliably.