DON'T FILE!
It sounds like you have a simple alignment problem. The carrier may not be properly positioning the shell, so it's catching on the mouth of the chamber.
This could be caused by a damaged carrier (or related part), foreign matter preventing its proper positing, or possible operator error. First give it a good cleaning, check for bad parts, and then verify that the carrier is functioning properly. Cycle some ammo through the magazine. If it cycles from the mag, but not from the breech, then there may be operator error involved.
Although many auto-loading shotguns are similar in appearance, they often have differing loading procedures. I'm used to my R-1100's operation: I drop one the ejection port, hit the release and it's ready to go. To many, that's the way auto-loaders work; but, there are differences. From the TriStar Manual's instructions for loading:
Be certain the safety is in the "on" position.
Press the magazine cut-off button located at the back of the loading port on the bottom of the receiver. This will lock the loading port. Draw or pull the bolt rearward until it locks in the open position. Place a shell into the breach. Release the bolt by pressing the button located toward the front of the receiver. This chambers a round and the gun will fire if the trigger is pulled with the safety in the "off" or "fire" position. You can then load additional shells into the magazine by inserting them through the loading port on the bottom of the receiver and pushing them into the magazine.
Did you push the mag cut-off button before loading via the ejection port? I'm not sure what the,
This will lock the loading port, is all about. Without the
locking, is the carrier properly positioned to ensure smooth chamber entry?
Since the TriStars accommodate several shell lengths, they may have some unusual ways of dealing with the situation. You didn't mention which model you have, does it have a 3 or 3-1/2 inch chamber? What size shells were you using on the clays? What length shells previously functioned successfully? It may be there is nothing wrong with your gun and you're doing nothing wrong -- it just may not like the shells you're trying to use.
