i bought a ramset cobra and went to use it in my basement to nail a shelf to the foundation wall. Basically i used a 2.5 inch nail through a 3/4 inch piece of wood. I used from the lowest to the highest power charge and all of them would not drive the nail fully into the wall. About 3/4 of an inch was left to be driven with the red powder charges. Am i doing something wrong or is that the concrete is just over 60 years old and is too hard for a nail of that size? Basically im left with some small concrete blowouts in the wall from pulling nails out, and the ones i shot with red charges i cant even pull out, the heads broke off after trying so hard to get them out.