I picked up 20 rounds of Bosnian ammo (headstamp IK-97 .50), is this easier to set off than the WW2 AP I have? Corrosive? etc etc.

the 'IK' headstamped ammo has been found to be mildly corrosive.   Not as bad as USGI WWII surplus, but you should run some HOT soapy water through the barrel then clean as normal.

The primers are as hard as the US milspec primers.

Make certain you got the hammer spring installed in the right direction when you put in the heavy duty replacement hammer.   You loose a bit of striking power otherwise.