When the A5 is fired the barrel will needs to recoil all the way to the rear position with the block locked. The block assembly locks at the rear as the barrel moves forward to eject the shell as the carrier dog will hold in place until the barrel extension get almost in the forward postion. First thing, polish tube to a high polish length wise. Must use a heavy grease on the all parts of the action inside the receiver and the magazine tube. We used Rig grease and that means to use plenty of grease. Oil doesn't cling to the parts. Grease up the inside of the barrel section that has the metal and brass rings slipping into. Look for a smooth section with the angle where the parts meet on recoil. Some times we would need to ream the barrel section inside to recut the angle section. The other thing to look for would be the locking block and the breech bolt. Sometimes the blocks will be cracked and the locking block rail on the side will be broken off. This would need to be check at a shop that does major repair on A5's. I fitted up locking blocks, breech blocks, and barrel extensions. You need reamers, headspace gauges, and the knowledge to perform these jobs if you are a warranty gunsmith shop. I tell all young gunsmiths to try getting a job for a couple of years in a major warranty shop for some OJT where you can get information that most smaller shops will never see. When I started in the early '60, the factory repair person would travel around to the shops and spend all day with us and cover many problems. Some A5's are still operating after 75 yrs of service.
