Just want to add that Donny's moderators Do NOT employ any sort of "plastic". Top notch machined components only.
Mike.
The Donnys I took apart used masking tape to hold the felt and steel mesh to keep them on the core, the Sumo used rubber o-rings at the ends, and the felt itself is a synthetic which based on the burn and sniff test I'm guessing is nylon. (which is a common plastic, just spun out into fibers and felted) None of those are "machined" components, in the conventional sense of the word.
My point? Plastics, rubbers, and other polymers form critical and integral components of Donny's designs, and virtually every other moderator design I can think of. That doesn't make them not quality, they're very nicely made, however there is absolutely nothing wrong with leveraging them in moderators. In fact, in my entire test, I can't think of a single moderator which definitively doesn't use a polymeric material of some sort somewhere nor airgun itself for that matter.
I hope that makes sense.
In fairness though, I don't think any manufacturer could sell moderators with very tight clearance to the general public without having problems.
This is a key point. While some baffle designs lean on tight pellet clearances to generate their performance more than others, largely tighter will improve performance..... but is also more subject to POI shifts and ultimately concentricity of the system. I suspect moderator companies would get a lot more bad press from accuracy/clipping issues than they'd gain sales from the minor sound attenuation benefits.
