Weihrauch HW100 T has become completely inaccurate

[jepho]

Hello all. My Weihrauch HW100 T was able to put pellet on pellet at 25 yards. Now it is behaving like a shotgun. A couple of weeks ago, I was unable to group with any accuracy. At 25 yards the rifle was grouping shots that could all fit under a 5p piece and most of them were pellet on pellet. The loss of accuracy was puzzling. I use the most consistent pellets I could find (RWS R10 Match).

Many suggestions were made and I exchanged the scope (mine has a glass etched reticle so it was unlikely to be the cause) and a gunsmith told me that the barrel had become loose and the silencer was bent out of true. He had apparently tightened the barrel and I bought a new Huggett moderator. The barrel of the gun was cleaned and today, I have had no success with grouping shots. The target still resembles one that was shot with a blunderbuss or a shotgun.

The images attached via dropbox are the target face with a moderator on and before barrel cleaning. The next image shows what was a potential group after the barrel was cleaned. It is a long way away from what I am used to. The final image shows that target face after the barrel was cleaned and the moderator was removed.

https://www.dropbox.com/sh/hxyps7ma7...th61b3PDa?dl=0

My questions: Has anyone ever seen this type of issue previously? The gunsmith said that the barrel was slightly loose and he had tightened it. The gun is around 2 years old. The chrony shows consistent figures with 10.5 fpe with 8.4 gr pellets (RWS superpoints) and 11.5 fpe with 7 gr, .452, R10 Match pellets. Small fps variations covering no more than approximately 9 fps for both pellet sizes and weights.

I am not sure what else to try. The seals all appear to be intact and there is no leaking from the cylinder when left. All suggestions welcome.