AC,
I am glad that your post was just as it appeared. I apologize again for being abrupt but I have seen too many "inflamatory" posts that are psoted just to get a rise out of people. They do get a rise out of me, especially if it goes against what I know from experience and they seem to be drawing from nothing.
Now the info from yor second post was good and enables up to be more helpful.
First off, about the 20 ga. 1100. The 1100 is a gas operated shotgun which bleeds gas from the barrel to unlock the bolt, allowing the backward inertia from firing shell to then push it to the rear and cycle the weapon.
Lets talk about the first action taking place upon firing. As the shell is fired, the propelling gasses are vented off, mid-barrel, and push on a rubber type o-ring and two piece seal made out of metal which are riding at the front of the slide action bar (forget the proper name) which is connected to the bolt. This unlocking can basically be affected by two things. Not enough gas to unlock the bolt or dirty or worn gas seal parts. The amount of gas produced by the shell is dependent on the type of shell used and I will discuss them below. Now about the gas seal parts. The rubber o-ring can get worn and torn up and does need to be replaced. Some people replace them frequently but I have had the same o-ring in my 1100 for quite some time. I think keeping the system clean plays a part in how they wear. The two piece gas seal can get dirty and they will need to be cleaned. These two pieces have a seal like a valve on a car engine and when these are dirty they don't seal well and can cause functioning problems.
Now when I clean my 1100 I wipe down the magazine tube, clean the o-ring and gas seal parts and then I coat the mag tube with a little CLP. Now you have to realize that when I clean my 1100 it is because I want to, not because I have to. This is not a dirt sensitive system and I proabably put 300-500 rounds throught my 1100 before it gets a cleaning. Those two boxes of 7/8 oz. cheap WalMart loads I put through it two weeks ago pushed it past the 400 round mark without a cleaning. I am sure the others on the list can comment about the cleaning interval for their guns.
Now about the shells. There are two main things about a shells that are important. The dram equivilant of the shell and what I call the payload weight or how much shot it has. The dram equivlant is basically the power rating for the shell. It is a old unit of measurement that has no real equivilant today but it is still used to rate the power of shotshells. The three basic dram ratings you see are 2 1/2 (or somewhere close) 3 and 3+ or MAX (Max being the most powerful). This rating is important but it is not the only thing to consider about the shells. You need to also factor in the payload weight. The amount of shot a shell has is also important to the functioning of the weapon. The more shot there is, the more back pressure there is to put more gas into the gas system (to unlock the bolt) and the more recoil there is to cycle the action. The payload weight and the Dram equivilant work togeather. Basically the lighter charge of shot you have the higher dram rating you need. Since the lighter charge of shot creates less recoil and less backpressure to cycle the action, it needs more power to make up for that deficiency. If you have a heavier payload you don't need such a high dram rating because it gives you more backpressure and recoil to cycle the action.
Now about your specific situation. I think the 7/8 oz. should work in your 1100. They work good in my regular 1100 and should work in yours. If they don't want to work or you want something with more power, get those 100 rd packs of Federal shells WalMart sells. They have 1 1/8 oz. of shot and are 3 dram (I think) and will even cycle my 11-87 Police that doesn't work with those 7/8 oz. loads. These loads are better for training since they give you a more realistic feel. Praticing with the 7/8 oz. loads and them using a heavier load (buck or whatever) for defense isn't realistic. As a general rule sticking with shells that have a heavier payload is more important than a higher dram rating.
Whew! that was allot of typing. I hope it made sense and was informative. If I screwed something up I sure the others on the list will correct me
If I didn't answer your specific questions or you have more, ask away.
[This message has been edited by Intel6 (edited October 25, 2000).]