Place masking tape over the indentation(s) on a magazine. I used my thumb nail to get the tape down into the recesses then using an ink pen traced around the recesses. You are making a mirror pattern, left side of the magazine I marked "RT" for right top. Remember mirror image... I bought 2" wide 3M abrasive tape from our local hardware (this sell it by the foot). This is the same stuff used on stairs and ladders to provide a non-skid surface. Gently remove the masking tape form the magazine and place it on the back side of the abrasive tape. Cut the abrasive tape following the ink line on the masking tape (I cut on the outside of the ink line). Remember mirror image...so if this pattern came from the left top of the magazine your cutout will go on the right top. Make sure your magazine is free from oils and dirt before placing the adhesive side of the abrasive tape on the magazine (dry fit first and trim if necessary). When done you now have a magazine with some "grip" to in to prevent slippage. Depending on the Pmag generation you can do the front if wanted. In my case I believe it adds a little zip to my current build too.