As well as designing and manufacturing our own sound moderators in house, we can supply and fit other makes when requested. Today was a Wildcat Predator 12 on a .308 Win Howa and as the Howa is pre threaded in 5/8″ UNEF it is just a matter of ordering it in and screwing it on, or nearly..
Firstly I like to correctly fit the rear bushing which means removing the bushing, screwing the moderator on, measuring the diameter of the barrel immediately behind the moderator and boring the bushing to suit.
People ask what the purpose of the bushing at the rear of a reflex moderator is and really, it serves a couple of purposes. Firstly it prevents excessive radial loads and damage to the moderator female thread where it is screwed on to the barrel and secondly, it allows the manufacturer to design a fairly generic back end to the moderator which can then be tidied up with the bushing.
I usually bore the moderator bushing with +0.25mm on the diameter of the barrel, or around 5 thou all round which is ample for expansion and general use. People ask why and there is an easy answer, it is my preference.
A Dremel is not the tool for opening the bushing and I seriously question why a person or shop would do this. It takes probably 25 minutes to measure, bore and fit the bushing, explain the safe use and maintenance of the sound moderator, fill in the table 1 of the new owners FAC and kick them out of the door and joking aside, I would always sooner spend 25 minutes explaining things and giving them a correctly fitted moderator, more to the point, we do not charge separately for this service.
I have read various views on bushing clearance and the implications of its lack of so I have added a picture of the moderator I run on my Accuracy International. It is a custom reflex with a stainless steel front and inner tube and an aluminium rear body, at the rear it is bushed with an internal O ring that contacts the barrel. Accuracy wise it works very well.
Once the bushing is bored and fitted I walk the customer through the do’s and don’ts of sound moderators. Never leave it on your rifle after you have been out shooting, regularly strip and clean the internals, keep an eye on any O’rings fitted and replace them if required and most importantly, lubricate the threads on the muzzle and the moderator with a wipe of copper grease or similar. WD40 will not do!
…and why am I telling you this? Because you need to know.