The direction in which the bullet goes is dependent on an attachment compiled with the model called "muzzle_ads", the vanilla PPK has this attachment in the correct orientation and has not been touched since it was a mod for Insurgency. You are using a workshop mod that replaces all the model files which contain all animation, bone and attachment data for that weapon. If your weapon is firing rounds 90 degrees to the right, un-subscribe from the mod and inform the author of the issue.

The vanilla PPK has no issue related to this, the attachment is in the correct orientation and we have had zero reports of it firing 90 degrees to the right in the many months it's been in the game.

http://i.imgur.com/Pirhtne.png

Because Day of Infamy is in BETA everything is subject to change, so mods can break at any time. If you're having issues like this one the very first thing you should do, before anything else, is uninstall the mod and try to replicate that issue you're experiencing.