Many of the problems I've seen with the 1100 were caused by the gun owner. The one I've seen most often is the incorrect assembly of the gas-piston seal, the gas piston, and the "O" ring or barrel seal. The gas-piston seal has one flat side, a groove in the center, and a bevel or taper on the other side. It's installed over the magazine tube with the flat side against the front face of the action-bar sleeve. The gas piston has a taper on one side and a reduced diameter step on the other. When installed, the taper on the gas piston matches and fits into the taper on the piston seal. Finally the "O" ring is placed on the magazine tube and pushed rearward until it's seated in a circular groove in the magazine tube. The barrel is then slid on the tube, completing the assembly of the gas-cylinder components.

Reversal of the piston or piston seal will cause major problems and lead to malfunctions. A trick I learned years ago is to make sure the slots in the piston and piston seal are not aligned. If the slot in the piston seal is positioned at, say, 9 o'clock, then the slot of the piston should be at 3 o'clock. If the slots are aligned, gas will leak from the system and cut into its efficiency.

The "O" ring is often stretched, mashed, or damaged in some way. Many folks are not as careful installing the "O" ring as they should be, and they inadvertently damage it. A damaged "O" ring will allow gas to leak out of the system and make it more difficult for the gun to operate properly.

For the gas to get to the piston and piston seal, it has to pass through a vent or port in the barrel. Depending upon the type of barrel, there may be one or more ports, and these ports can vary in size. The ports can and will clog up over time with carbon and plastic wad fouling. As the openings in the ports foul, they become smaller, and less gas can be vented into the gas system. For high-pressure loads, that may not be a problem, but for light loads, that can often make the difference between functioning and malfunctioning.

While most shooters will do a good job of cleaning the inside and outside of the barrel, many never think to clean the gas ports. If you have a set of drills and a pin vise, that's all you need to clean the ports. First, find the drill bit that will just pass through the port into the barrel. Install the bit in your pin vise and use it as a reamer to clean carbon or plastic fouling from the port. Be careful not to scratch the inside of the barrel with the tip of the bit. As you turn the bit by hand, you'll be able to tell if you're scraping out fouling. With just light finger pressure, you shouldn't have to worry about enlarging the port.

Speaking of enlarging the gas port, a lot of folks want to do just that to solve any functioning problem. Generally, that's not a good idea. True, you can open up the gas port and vent more gas into the system. However, what happens when you shoot heavy loads through that same barrel? You vent out more gas, and this can cause severe wear and tear on your gun. I've seen guns that were literally battered into junk because someone thought, "If some gas is good, more gas is better!" Friends, this ain't chocolate cake or grandma's cookies. More is not necessarily better, and it can sure cause severe problems.