Thread: Bergara B14 rifle

Fire-cracking - when the cartridge is fired in the barrel chamber a very hot flame follows the bullet down the barrel. The flame erodes the bore of the barrel. If you have a look with a bore-scope you may see a longitudinal cracked/eroded surface for a larger or lesser distance down the bore from the neck of the chamber. Overbore cartridges are more prone to firecracking than underbore cartridges. An example of an overbore cartridge is the 243Win. An underbore cartridge example would be the 7.62x39. The larger the amount of powder for the smaller the bore, the greater the effect of firecracking. I first saw this inside the bore of my Sako 243Win. The barrel had 750 counted rounds through it and the bore was significantly firecracked for a few inches of the bore and was losing accuracy. The more shots taken in the shorter time, the worse the firecracking becomes. The 750 shots were mostly hunting rabbits at longish ranges, with significant cool down time between shots. 750 rounds out of a 243Win is getting to the point of no return due to the firecracking. A new barrel and getting it fitted was a significant cost. So, each of those shots was not just the cost of the cartridge but also the erosion of the barrel. If the firecracking becomes too rough it may damage the bullet so that the bullet does not just become less accurate but comes apart rather than reaching the target.