Stepped Down Diameter Thread Section Original Parker Hale Sound Moderator.
Apparently these options are supposedly ‘impossible’ to find and were specific to certain training / older rim fire rifles.
I actually have a selection of the more standard versions parallel along their entire length as well as these.
ANY and ALL Pre-used Sound Moderators I have should offer up perfectly acceptable performances. Certainly comparable to the equivalent model brand new. Given they are very likely to already be ‘carbonised’ internally there is every chance they will actually increase effectiveness. As with anything not brand new there is a chance they may well not last as long. However this IS reflected in the price. In reality, unless you are regularly spending hours on a range, there should be way over enough ‘life’ still there for the average shot.
The ONLY way to get maximum longevity is to dig that bit deeper and buy new. Happy to order those in where needed so just ask if you prefer.