This is a rather commonly occurring problem with any number of ejector guns. Merkel had more that their share of it. What happens is the ejector tumblers in the forend become tripped and the forend cannot then be easily mounted. A good "trick" shown to me many years ago is to simply dismount the barrels, move the extractors out and mount the forend on the barrels (off the gun) now take a piece of wood and push each extractor, one at a time, back into it's seat. Now you should be able to remove the forend and assamble the barrels and forend. Parkers can easily have the same problem. A good "trick" to know when you are out in the woods trying to get your gun together...