From what I have read is how much, or any, it helps is dependent on the amount of gas that leaves the can and hits the brake. The more gas, the more it works. Some short action cartridges with longer barrels, there isn't gonna be a big rush of gas out the front, its going to have expanded in the barrel and the can, so the brake won't be as effective. But with shorter barrels or long action cartridges with more powder burning, there is much more gas hitting the brake, making it more effective. Again, this is just my understanding of it and please excuse my very technical explanation there...