Beneficial effects of moderators with HV rounds


Contract research report I found from HSE relating to effects of moderators on centrefire and rimfire rifles in relation to noise suppression and recoil suppression.

Tests were carried out to see if moderators had any beneficial effects under normal deer/vermin control conditions i.e. using high velocity rounds.

Some points I found interesting, you might not.

1) some ear defenders are doing very little, with low dB reduction and in some cases having a negative effect as the cheek piece recoils and strikes the ear defender cup, causing louder sound levels inside the muff compared to outside. Overall though ED still recomended with CF rifle and moderator but not needed with 22lr and moderator

2) accelerometer data showing up to 30% reduction in recoil when some moderators used.

3) Some moderators worked better than others and no significant difference between reflex and normal design. Some other Finnish research by gun make here

If you are no longer armed services (crown immune) and paid to cull you are "at work" and should consider if this is a benefit to you.

If nothing else it makes a good legal reason to have a moderator on the grounds of your personal long term health. The report suggests to me that using a moderator is best practice. It also protects your dog if you have one with you.

Do not know enough to judge what this means for realistic shooting of deer but thought it may be of general interest.

Interesting post, but it is rather old news. About 8 years ago, a number of Forestry Commission rangers made it very clear to the Police and Home Office that they would sue under HSE laws if variations were not granted for moderator use on fullbore rifles. At the time, the Police looked on suppressors as nasty evil things. New guidance was issued in 2001 and these days it's getting rare to see a stalking rifle without one!
When I applied for an FAC I asked that all the rifles be allowed a moderator,
AND I fully expected to have to justify my request.

Not so! My FEO (Kent Police) said that had I not asked he would have added them anyway


A lot of the studies were done by Finns and used by BASC with the FCS lads as the means to force the issue!


I dont bother with them although I can see a day when they will be mandatory!


Reduced or dissipated energy going forward, Newtons law of something or other and less energy going backwards. The energy (sound and gas) makes the moderator hot, this is transferrance of the energy!
Cheers Ugly. Energy/gases not being allowed to go forward but being tapped off sideways into the moderator. Just would never have thought that would have such a significant effect but it does make sense the way you explain it.

Thank you.
The physics bit: "every action has an equal and opposite reaction".
Soak up some of the target bound energy and hey presto, you soak up some of the shoulder bound energy.
Added bonus, make the weapon heavier by adding more bits and its harder to push, just like the Ford Escort.
Sorry showing my age there.

Best wishes from the FC lads who did the deed!

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