A very important aspect of having a moderator (or any other barrel device such as a flash hider, muzzle brake etc.) fitted to your rifle, is to ensure that the appropriate thread is cut to close tolerances (preferably a C3 fit, meaning that the device will screw onto the barrel without any undue force but also without any play on the threads, or at worst a C2 fit which means only the slightest of play on the threads) and absolutely parallel to the bore.

The most common mistake made when cutting thread on a rifle barrel is that the person doing the machine work assumes that the bore is in the center of the barrel and that the barrel is straight. This hardly ever is the case.

Think about it – how easy should it be to drill a 32 inch deep hole perfectly straight? No easy feat even for machine shops with the most advanced machines. Then there is all the accompanying stresses induced in the barrel steel during the rifling and profiling phases of manufacturing.

All major barrel manufacturers stress relieve barrels several times during the manufacturing process and finally straighten it as good as possible.

It is thus imperative that you take your rifle to a competent gunsmith with the ability to dial indicate the last inch or two of the rifle BORE to within .0005 of an inch or less before commencing with cutting of the thread.

This is the ONLY way to get the accuracy and service from your newly acquired muzzle device. Thread not cut parallel to the bore are a sure recipe for bullets touching baffles or muzzle brakes.

If your gunsmith cannot indicate your barrel of the bore, look for another.

This is the single most important aspect in having your CMG Recoil Reaper (or whatever device you chose) perform to its full capability.

The second important part to proper thread and thread selection is to ensure that there is enough metal left around the bore but that there also is a proper shoulder for the moderator (or muzzle brake etc) to seat against for the final alignment and fastening.

Also ask your gunsmith to make you a thread protector (also called a nosecap) to protect the thread and keep it clean when your moderator is not in use.

Standard available threads include:
12 x 1.0
13 x 1.0
14 x 1.0
15 x 1.0
16 x 1.0
17 x 1.0
18 x 1.0
20 x 1.0
All threads supplied are metric fine thread, contact us should you require a special thread for your rifle. Most common imperial threads (for example):
5/8” x 24 tpi
½” x 28 tpi

When attaching your moderator, first make very sure the rifle is not loaded.
Remove the thread protector. Visually inspect both threads and make sure there are no burs or dirt. Look trough the moderator to ensure there are no foreign material, dirt or obstructions that may negate the safe passage of bullets. Carefully start threading your moderator onto the barrel making very sure you don’t cross thread it.

Stand the rifle upright on the ground, resting on the recoil pad that is now between your feet. With slight pressure of your knees on the fore end and your feet on the buttstock, firmly snug the moderator up to the shoulder and physically inspect the fit between the shoulder on the barrel and the back of the moderator. It should be a nice solid fit with no light visible.

Finally remove the bolt from the action and look through the bore from behind the rifle. An even shadowline created by the additional length of the moderator should be seen. If this shadow line is larger at any point it says that something is not properly aligned. Remove the moderator and clean all threads. Refit and recheck. If the problem persists contact your gunsmith.

After two shots check that the moderator is still tightly locked against the opposing barrel shoulder.

Recheck after another 5 shots.

Bear in mind that your rifle was taken apart for the thread cutting operation. The scope was off, the stock and trigger removed and the barrel possible removed from the action.

Because of this it is always a good idea to first fire a five shot group without your moderator to ensure that the rifle is shooting as usual. If not, you will immediately know that something is amiss with the rifle, scope or stock.

This will save you a lot of trouble. If the moderator was fitted at this stage, you would probably have jumped to the conclusion that the problem lies with either the thread or the moderator.

The point of impact can vary considerably depending entirely on your specific rifle/setup. It may be as close as an inch or as much as five to six inches away from the previous point of impact.

Our experience is that most rifles will shoot better groups with the CMG Recoil Reaper and some dramatically so. Again all depends on your specific rifle and how sensitive it is to any changes. In extreme cases it might even require fine tuning your loads or changing to a different brand of ammunition or different bullet weight, although we have never experienced this. In our test rifles all brands of factory ammunition shot much better groups – all well under an inch at 100 meters.

All other rifles that we have tested shot at least as well as it used to and most shot much tighter groups. As said previously, this was never the intention and came as a huge bonus. Recoil and noise reduction was the two main goals.

Should your rifle not group well with the moderator attached or if it misses the target all together, it may well be that the bullets are touching the baffles or muzzle brake. Small burs might be raised around the baffle holes after a few rounds due to the extreme pressure inside the moderator. These are easily removed by using a drill of equal size to the holes in the baffles and working it by hand to and fro from both ends of the moderator.

The other possibility is that the thread on the barrel weren’t cut correctly and thus misaligns the moderator.

Consult your gunsmith should this be the case.

Apart from the two scenarios mentioned above, we have had no problems with rifles not shooting extremely well with the CMG Recoil Reaper.