Thank you all for the good information. Good shootingThe 20 ga. inserts work fairly well in a 12 ga. however the 28 ga and .410 versions not so much. The original short Side Kicks have all the issues noted above however, Briley has improved the situation by adding a barrel extension on the 2.0 versions (much like their original .410 models). The longer 2.0 versions should improve combustion and reduce blowback some. You might want to look for a set of Seminole Chambermates or Rhino Stingers as they both had O-ring seals to reduce the blowback and Rhinos have the long tubes also. For most fun shooting, you should be happy with the performance of most of the 12 to 20 ga. options as long as you are willing to do the extra cleaning. It was hard for me to get used the extra swing weight (inertia) of full length tubes. Good luck.