Eric
All the statements made are correct, my wife shot an LGR at international level in the 80's, still has it, has just returned to shooting and is still using it and is not interested in changing to any thing newer. They are easy to work on, I changed the valve, buffer, and breach seals before she restarted and it performs perfectly.
If you want to try both we have them as club guns at our target club in Norwich, you can e me on robin.carter80@ntlworld.com for details
elewis
The following procedure is the official way used by Walther to ensure the seal fit is correct and with no leaks. When you change the breach seals, it is very important to clean the old ones out of the block carefully as some were put in with something like loctite and if not cleaned out it causes the problem you describe. I refit them dry which is no issue unless the block has been butchered, the block is alloy and if the seal recesses have been scrapped out it may be best to replace the block. With the rifle held in a vice by the barrel (pad with cloth and wood) vertically, action up, slacken the barrel lock screw with an allen key and with the breach closed let the weight of the action settle and then just nip the lock screw and check the breach block fit. It should be firm with no noticeable movement, I sometimes give the action a very light tap with a soft mallet with it nipped to get that last thou of movement out but take care to not over strain it other wise it will pop open in use. Its a delicate operation to get the ballance of no movement with out over crowding it. When correct, tighten the barrel lock screw, there is no torque setting but it should be very tight, and then recheck that the fit is the same after it is all tight. In use don't snap the block closed, lift the tab, close the block and close the tab.
Best regards
Robin