Wildcat Whisper Specifications

Price (RRP): £120
Thread: ½ inch UNF
Weight: 160g
Design: Reflex
Overall Length: 175mm
Diameter: 36mm
Forward Protruding Length: 100mm
Calibre: Available for both .17HMR and .22RF (.22RF Being Reviewed)
Max. Barrel Thickness: 24mm
Manufacturer: UK Custom Shop Ltd (Wildcat)
Manufacturer Website: http://www.wildcatrifles.co.uk/
Country of Origin: England

First Impressions of the Wildcat Whisper

The build quality on this moderator is great. This mod is made from coated stainless and what seems like anodised alloy. Perhaps the most striking thing about the Wildcat moderators is the use of colour coding, so that at a glance you can see the calibre of the moderator that is being used. In this case, since its .22 calibre, the end of the moderator is purple.

Wildcat Whisper Moderator Next To Tape Measure

Wildcat Whisper Moderator Next To Tape Measure

The mod is made in 3 parts and easily strippable for cleaning.

Customer Service was excellent. Unfortunately when I first tried the moderator on my Sako the Point of Impact moved around 15” at 25 yards and the bullets appeared to be going through the target sideways.

Keyholing Bullets After Clipping Moderator

Keyholing Bullets After Clipping Moderator

After a little investigation with both this moderator and my SAK moderator with a cleaning rod, it appeared that the thread of the rifle was cut (by an unknown gunsmith, as the work was done prior to me purchasing it) to the outside of the barrel and not the inside of the bore, this was not enough to affect the bullet trajectory on the SAK moderator as it has a wider exit hole than the Whisper by some 1.8mm.

Exit Hole Size of Wildcat Whisper Moderator

Exit Hole Size of Wildcat Whisper Moderator

UK Custom Shop helped me out by getting the thread on my rifle re-cut by their gunsmith to the bore of the rifle and it now shoots superbly with either moderator. Alison went above and beyond to help me out. Definitely a company big on customer service.

Wildcat Whisper Effective Moderation

This is not meant to be a Laboratory test, but an effective, repeatable test that can be used to compare against other moderators.

To test the effective moderation of the Wildcat Whisper I took a sample of 10 rounds unmoderated to give a baseline average unmoderated sound level on the rifle in question. A cut down heavy barrelled Sako Finnfire. The ammunition used is Batch Tested Lapua Centre X – This ammunition was the most accurate batch at 50 yards, one may speculate that is was therefore the most consistent, which makes it perfect for this test.

This ammo is deliberately sub-sonic. I don’t want the supersonic crack provided by some ammo to influence the SPL reading.

Prior to this test, the only thing that concerned me was due to the test being conducted on a range with a steel walled butt-stop the ring of the bullet hitting the steel may have skewed the results, as it happens it this concern was unfounded.

The test was conducted on a closed indoor range at 25 yards, the sound buy xanax mexico online pressure measurement was provided by a Testo 815 Sound Level Meter placed 60cm (As illustrated by the yellow and black tape) from the muzzle at 90° with the microphone pointing directly at the muzzle.

The Tester had been calibrated at some point during its lifespan – for a guide, the background noise on the range is less than 60db, and the sound of a door closing on the range at 6 feet away was 70.3 db(a).

Sako Finnfire Unmoderated Sound Pressure Level Testing

Sako Finnfire Unmoderated Sound Pressure Level Testing


1st. 109.8 db(a)
2nd. 109.8 db(a)
3rd. 108.2 db(a)
4th. 108.5 db(a)
5th. 107.9 db(a)
6th. 108.9 db(a)
7th. 108.7 db(a)
8th. 109 db(a)
9th. 107.4 db(a)
10th. 108.5 db(a)

Average Unmoderated Level: 108.67 db(a)

I then screwed on the Wildcat Whisper to the barrel and did the exact same test as outlined above.

Sako Finnfire Wildcat Whisper Moderation Sound Pressure Level Testing

Sako Finnfire Wildcat Whisper Moderation Sound Pressure Level Testing

Moderated with Wildcat Whisper

1st. 89.1 db(a)
2nd. 91.2 db(a)
3rd. 92.4 db(a)
4th. 90.7 db(a)
5th. 91.8 db(a)
6th. 90.8 db(a)
7th. 92.8 db(a)
8th. 90.7 db(a)
9th. 92.3 db(a)
10th. 91.8 db(a)

Average Moderated Level: 91.36 db(a)

This gives us an average effective moderation of 17.31 db(a)

And a cost per DB of moderation at £6.93 per DB(a)

Cleaning the Wildcat Whisper

As mentioned above, this moderator is user strippable and easily cleanable. UK Custom Shop advised that it could be used in an ultrasonic bath and that some customers had even reported that they had been throwing them in the dishwasher (don’t tell the wife!) and so long as they are dried thoroughly, oiled and O-rings greased as per the recommendation the moderator should last a very long time.

Stripped (Dirty) Wildcat Whisper .22LR Moderator

Stripped (Dirty) Wildcat Whisper .22LR Moderator


As this moderator is a Reflex Moderator (Over Barrel), it is worth mentioning that if your rifle is a hunter rifle, for which many people in the UK will use moderators on, you may need to check that it does not have a foresight which will impede the fitting of this suppressor to your rifle.


The effective moderation test within this article is for comparative use only, using the same methodology and equipment. This article is not compliant with any standardised military test or equipment. Figures should be used as rough guides. The author always advises the use of ear protection along with moderators as additional hearing safety. Once your hearing is gone, it’s gone. Be careful out there.