I’m looking for a moderator that won’t throw off shots when shooting slugs at high speeds. 25 grain and up slugs at 950+ FPS. Thoughts?
Rifle: FX Impact 700mm
Rifle: FX Impact 700mm
Last edited:
What’s the most harmonically balanced moderator one can buy?
- Thread starter Maizen
- Start date
I doubt there's one answer. Your barrel has a natural harmonic mode, like a spring constant. The moderator most suited to your barrel will depend on whatever the spring constant is for your barrel. When you say "throw off shots" I imagine you are talking about relative to when you have no moderator, i.e. you want it to not affect your barrel's mode of vibration.
i.e. you'll want a moderator whose length and weight (as well as internals, inertia, etc) don't affect the mode of vibration of your barrel. That said, I'd be curious at what distance these differences become noticable.
Upvote 0
Try a Silencer Thunder Ordnance Falx high flow.
I have 1 on my .25 M3 700mm. I shoot H&N 40gr Heavy slugs @970fps.
www.silentthunderordnance.com
I have 1 on my .25 M3 700mm. I shoot H&N 40gr Heavy slugs @970fps.
Falx — Silent Thunder Ordnance
The Falx carries a dimensional envelope of 40x170mm, ~180 grams, with a semi-modular serviceable aluminum-tube design. The same proven principles of air stripping, flow delaying, and sound absorption remain but now in an even more advanced form. This brings improved manufacturability, reducing price
www.silentthunderordnance.com Upvote 0
The FALX works very well, wish that I hadn't sold the one that I used on my Crown. Would have worked great on my M3 now.
Upvote 0
I believe the question you are asking is what can I do to tune the moderator I have to run on the rifle/ammo combination I am using. I could be wrong but this is an easy way to tune your setup once you have everything you want running the way you want.
I have observed that two factors are very important when you are seeking accuracy from a moderator. I believe the most important is the jump from the muzzle to the first baffle. That first baffle acts as a stripper redirecting the muzzle blast away from the path of the projectile until it gets to the second baffle or gets far enough ahead of that cloud of turbulent gas that it (the gas) can't catch up and destabilize the projectile. This distance can be adjusted by adding/subtracting very thin shims (0.5mm or so) at the interface between the barrel and the moderator. That presumes the designer understands this principle and addresses it in his design. Most either do not or simply believe it can't be addressed. That's why they have not YET figured out to ship those shims with their moderators. Keep watching.
Now the other factor; the barrel harmonics are altered by the weight of the moderator on the end of the barrel. When the barrel vibrates during the shot, it vibrates with multiple frequencies, not just one. Those frequencies add and subtract along the length of the barrel and create nodes of greater and lesser movement at different points along the barrel. Long whippy barrels are worse than short stiff barrels. Nothing new about this information, everyone knows it. It has also been long understood that adding a muzzle weight can sometimes tune a barrel to be more accurate. Well that moderator IS a muzzle weight. Getting that muzzle weight in exactly the right place will mitigate some of that movement. Again this can be at least partially solved by adding/removing shims at the interface between the moderator and the barrel. That is another reason why designers SHOULD be recommending to builders that a set of shims be shipped with a moderator for end user tuning.
Lastly this method of tuning impacts the sound signature of the moderator. Whether that works to improve quieting or not is pretty much a roll of the dice, but it does change the signature so it can be used for that purpose.
Bottom line though, you don't need someone to build that in to a moderator. You can find shims or make them quite easily. So here is an example of what I am trying to explain.
Tuning - Tuning Tanto Install on an HW98
I've been shooting this HW98 for several months now. It is a fine rifle. The trigger is excellent for a bone stock Rekord. It is a two stage with a clean pull to a second stage which creeps a tiny bit but breaks around 20 ounces. All in all quite manageable. The rifle has a "muzzle...
www.airgunnation.com Last edited:
Upvote 0
Mufasa,
Identifying the best harmonically balanced moderator depends on what gun it is attached to. As you mention and FX Impact with a 700 mm barrel, your question can be narrowed down.
Other than test data that we can analyze, I have a hunch that FX company might be able to recommend mufflers for you to try. I have noticed that the South African crew that promote FX products seems to have drifted from the FX branded DonnyFL suppressors, to some homebrew reflex suppressors.
I think that if one scans video footage of recent airgun competitions where FX dominates, then the suppressors they are wearing might offer a clue. Plenty of footage here:
Other than tuning the barrel harmonics via the suppressor mounting distance, you can and should tune your regulator and hammer strike etc to achieve the tightest group with a given projectile, and most consistent shooting with whatever suppressor you end up with.
Identifying the best harmonically balanced moderator depends on what gun it is attached to. As you mention and FX Impact with a 700 mm barrel, your question can be narrowed down.
Other than test data that we can analyze, I have a hunch that FX company might be able to recommend mufflers for you to try. I have noticed that the South African crew that promote FX products seems to have drifted from the FX branded DonnyFL suppressors, to some homebrew reflex suppressors.
I think that if one scans video footage of recent airgun competitions where FX dominates, then the suppressors they are wearing might offer a clue. Plenty of footage here:
Other than tuning the barrel harmonics via the suppressor mounting distance, you can and should tune your regulator and hammer strike etc to achieve the tightest group with a given projectile, and most consistent shooting with whatever suppressor you end up with.
Upvote 0
Good information. Should one tune the rifle first (reg & hammer) or the moderator?I believe the question you are asking is what can I do to tune the moderator I have to run on the rifle/ammo combination I am using. I could be wrong but this is an easy way to tune your setup once you have everything you want running the way you want.
I have observed that two factors are very important when you are seeking accuracy from a moderator. I believe the most important is the jump from the muzzle to the first baffle. That first baffle acts as a stripper redirecting the muzzle blast away from the path of the projectile until it gets to the second baffle or gets far enough ahead of that cloud of turbulent gas that it (the gas) can't catch up and destabilize the projectile. This distance can be adjusted by adding/subtracting very thin shims (0.5mm or so) at the interface between the barrel and the moderator. That presumes the designer understands this principle and addresses it in his design. Most either do not or simply believe it can't be addressed. That's why they have not YET figured out to ship those shims with their moderators. Keep watching.
Now the other factor; the barrel harmonics are altered by the weight of the moderator on the end of the barrel. When the barrel vibrates during the shot, it vibrates with multiple frequencies, not just one. Those frequencies add and subtract along the length of the barrel and create nodes of greater and lesser movement at different points along the barrel. Long whippy barrels are worse than short stiff barrels. Nothing new about this information, everyone knows it. It has also been long understood that adding a muzzle weight can sometimes tune a barrel to be more accurate. Well that moderator IS a muzzle weight. Getting that muzzle weight in exactly the right place will mitigate some of that movement. Again this can be at least partially solved by adding/removing shims at the interface between the moderator and the barrel. That is another reason why designers SHOULD be recommending to builders that a set of shims be shipped with a moderator for end user tuning.
Lastly this method of tuning impacts the sound signature of the moderator. Whether that works to improve quieting or not is pretty much a roll of the dice, but it does change the signature so it can be used for that purpose.
Bottom line though, you don't need someone to build that in to a moderator. You can find shims or make them quite easily. So here is an example of what I am trying to explain.
(C) M.Erskine, THIS INFORMATION AND THESE METHODS ARE PLACED IN THE PUBLIC DOMAIN AND MAY NOT BE PATENTED OR COPYRIGHTEDTuning - Tuning Tanto Install on an HW98
I've been shooting this HW98 for several months now. It is a fine rifle. The trigger is excellent for a bone stock Rekord. It is a two stage with a clean pull to a second stage which creeps a tiny bit but breaks around 20 ounces. All in all quite manageable. The rifle has a "muzzle...
Upvote 0
I think that's probably going to vary depending on who you ask. I would assemble the rifle into the configuration that I wanted including mounting the moderator with no spacers or washers. Then I would tune the rifle to shoot the pellet that I wanted the best I could. After I had all that done then I would shim the moderator.
The way I did it on the 98 including the graph is probably the easiest way to get it right. Using the graph you can see the trends and you can see how harmonics are affecting the point of impact.
Last edited: