I've used .22 air rifle, 22lr and 12b shotgun so far. The 22lr high velocity rounds penetrate the target without exiting the target where it's thicker than 6mm. When using the air rifle, you just get ricochets. Similarly with the No 5 cartridges but not as bad. It does handle the large loads like 00buck very well. Not used centre fire rifles yet, I would imagine centre fires get the most benefit from this product.