We had two photos on file shooting 300 PRC through the Magnus. 26" barrel if I remember correctly. One of them had zero signature visible (ie no spark / no flash) even when I cranked up the exposure using the raw image tool. Here is the second, I cranked up the exposure +3.5 and you can see one Ti spark and no flash. Flash is very much ammo and barrel length dependent. Ammo was Hornady 225gr ELDM.
View attachment 8189407
To scale, the length of the spark is about 3-5 inches in that exposure.
The noise in the photo is due to long exposure, high ISO, and increasing the exposure using the raw image tool and should give an idea how dim this is to start with