I wanted to run extended tube CMI Government length eight round magazines in Officer's size frames so I bought a couple of their SBP Extended Bumper Pads which Check-mate uses on their 10 round magazines to experiment with. The next thing I did was disassemble a standard eight round mag, cover the bottom third of it with Dykem, lock it into an Officer's Model frame, and carefully use the bottom of the frame as a guide to mark its outline onto the magazine. Then I reassembled the mag and measured from the bottom of the mag pad up to the lines scribed into the Dykem and transferred those measurements to the new bumper pad. Here's a pic of the Dykem applied to the first mag. If you look closely, you can see a thin white line where I scribed the outline of the frame onto the mag. After that it was a simple matter of cutting, filing, and sanding the polymer base pad until it allowed the eight round mag to seat into the Officer's frame. Now the eight round mags cannot be over-inserted, they run perfectly, and will be used as CCW spares on my belt. Below are some pics of a Colt CCO that I tweaked a few years ago and one of my favorites for CCW (new sights, trigger, grip safety, slide stop). This first pic shows it with a standard, flush fit six round mag in place. Here it is with a standard eight round mag fully seated. You can see the problem I was attempting to solve with my experiment. Over-insertion is definitely a concern here. Finally, here it is with the same eight round mag seated but with my homemade bumper installed. A perfect fit, if I do say so myself. Problem solved. Below are three magazines so you can see the differences. Standard flush fit six round, standard eight round extended tube with standard bumper pad, and standard eight round extended tube with homemade bumper pad. Below is what the SBP Extended Bumper Pad looked like before and after my surgery on it. Every mag I have gets heavily used on the range and during IDPA matches. These are no different. In fact, the eight round mags that have these new base pads have already seen hundreds of rounds through them with no malfunctions.