I got a Thompson Machine Zephyr XL from QRF this past summer (purchased last October)... It is incredibly quiet. Everyone who has shot the thing has commented on it. I haven't had a problem taking it apart to clean it yet and at half the cost of the Sparrow, I'd consider it.
I was originally looking at getting an Osprey and wanted the same things you did as far as caliber interchangeability- I ended up with the TM Zephyr and a Guardian 9 for the same cost as the Osprey. So far I don't regret the decision.
I was originally looking at getting an Osprey and wanted the same things you did as far as caliber interchangeability- I ended up with the TM Zephyr and a Guardian 9 for the same cost as the Osprey. So far I don't regret the decision.