Silencers, moderators?

Sounds like youd be better off switching to a .177 using moster RDs. Muzzle report as long as it is semi quiet is not really the main concern with spooking game. Unless they know the sound.

within reason quieter is better reason being the keyword ... putting a foot-long extended can on my rifle does 'nothing' for its usefulness in the field, especially if it already comes shrouded and isnt too loud, pretty dumb if you ask me lol ... however, if your shooting your .50 in the backyard of your suberbian palace a nice big moderator setup is just what you need so you dont scare the straights lol ..

I will use a moderator for backyard target shooting but I don't think I need one for hunting. Outside at 25 feet I measured my 50 fpe Avenger 25 caliber at about 90 db without a silencer today. Game will notice that but it doesn't threaten my hearing. But neighbors will notice it too. I put a home made moderator on it today, made from a sprinkler. It reduced the report to the low 80s. I am working on a bigger one that should get the noise down into the 70s. But that is still well above ambient in my neighborhood and especially in the woods. I doubt you can make any gun quiet enough game doesn't notice it. A really big can might get the report down into the 60s but that is still louder than the woods background noise.

My little 18 fpe Prod is quieter but only about 8 db. So it would be easier to moderate down well into the 70s, possibly the 60s. But I doubt it will get under 60 db on any silencer I want to use on it. I will probably but a little one on it and let it be in the upper 70db range.

70-80 db seems reachable, in other words, but not much quieter than that. That should not annoy neighbors but I don't know if it will scare off game or not. My guess is it still will.

I plan on running a short moderator on my AEA HP Bullpup when it arrives. The thing is when you are hunting, there may be game all around you, and you don't want the game close to you to be spooked because they heard the shot. There is nothing you can do with the downrange thwap that happens when connecting game outside of using lead free pellets that don't deform and dump their energy at the target, but what fun is that?

I don't believe so. I use a tiny one just to save my ears.

Long barrel has it equipped, but normally I use the short barrel too 

I have shot many a squirrel with a suppressed .22 LR, which is "Hollywood" quiet.

Squirrels will spook after the shot for two reasons: first, they hear the bullet fly and a loud pop as it hits its target. Second, the animal hit begins kicking and falls from the tree. You don't need to be educated to know this is all bad and time to get moving! Animals watch each other for any sign of danger, and they know when something is wrong.

What is there to gain? Your hearing for one. Another, you're less likely to draw attention to the fact your hunting or where you're hunting. Last, game doesn't know where the shot came from and may retreat in your direction, offering another chance to bag game.

My Avenger and Prod are both shrouded. Outside at 25 feet in front of my Avenger I measured just over 90 db. The Prod is 6-8 dp quieter. I don't think either will harm my hearing. So I am not planning on using a moderator hunting. But for back yard target shooting, I will probably start using one just to avoid annoying neighbors. Shot count is also much larger making holes in paper making even these moderately large sounds a little more of a risk.

So far I am just using a home made moderator made from a cheap used sprinkler head. Seems to reduce the Avenger by 9 db outside - gets it down to about 80 db. Looks terrible, however. I got the idea off a you tube. Only thing I paid for was an iron 1/2 NPT plug I could drill and tap to attach to the DonnyFL adapter.

I'm working on a couple others that will look a bit more normal and hopefully work as well or better. They will have a piece of aluminum tubing 3/8 ID, 5/8 OD in the center which I will drill and tap to attach to the Donny FL adapter on the Avenger. It will have holes to let the air out into a chamber made with schedule 40 PVC I had on hand. The 8 inch has a larger volume than the sprinkler one and the 4 inch has a smaller volume. Three data points will let me test the theory that more volume in the moderator = lower noise, and by how much. The PVC is cut and the plywood plugs to hold the aluminum tube and close off the PVC are made. I'm waiting on McMaster Carr to deliver the tubing.

Point of bringing these up is that you don't necessarily have to spend a lot to try out a moderator.

My Avenger and Prod are both shrouded. Outside at 25 feet in front of my Avenger I measured just over 90 db. The Prod is 6-8 dp quieter. I don't think either will harm my hearing. So I am not planning on using a moderator hunting. But for back yard target shooting, I will probably start using one just to avoid annoying neighbors. Shot count is also much larger making holes in paper making even these moderately large sounds a little more of a risk.

So far I am just using a home made moderator made from a cheap used sprinkler head. Seems to reduce the Avenger by 9 db outside - gets it down to about 80 db. Looks terrible, however. I got the idea off a you tube. Only thing I paid for was an iron 1/2 NPT plug I could drill and tap to attach to the DonnyFL adapter.

I'm working on a couple others that will look a bit more normal and hopefully work as well or better. They will have a piece of aluminum tubing 3/8 ID, 5/8 OD in the center which I will drill and tap to attach to the Donny FL adapter on the Avenger. It will have holes to let the air out into a chamber made with schedule 40 PVC I had on hand. The 8 inch has a larger volume than the sprinkler one and the 4 inch has a smaller volume. Three data points will let me test the theory that more volume in the moderator = lower noise, and by how much. The PVC is cut and the plywood plugs to hold the aluminum tube and close off the PVC are made. I'm waiting on McMaster Carr to deliver the tubing.

Point of bringing these up is that you don't necessarily have to spend a lot to try out a moderator.

Click to expand...

That may work out well for quieting the air rifle, but you may get yourself into a pickle with the law if they determine that it can be used on a firearm. At least with a DonnyFL purchase, you can claim that you purchased a purpose built air rifle suppressor to be used just on air rifles. Hopefully, it never comes to that. But that is one of the reasons I always keep my DonnyFL red tube with me when transporting my air rifle, just in case I get pulled over by a supercop who wants to find trouble.

It is a risk to assume people will be logical but I am pretty comfortable that a plastic bodied moderator is not going to work on a powder burner. Their pressure is much higher and the temperature of the gas they emit is too. If anything, an aluminum moderator like I assume the DonnyFL are, would be more usable on a powder burner since they can take the heat and may withstand the pressure of a rimfire. 

I would not argue with a strategy of sticking with a commercial moderator, however. I may end up there myself. But not because I'm worried about legality. Airgun moderators are legal in the U. S. where I live and I am confident it doesn't matter if you make it or buy it.

JimD, be very careful with the words "powder burner." There are strict laws and a list of NFA suppressor parts on the Alphabet org website.

Airgun moderators are designed to self-destruct if used on anything but airguns, and let's keep it that way.

A must for me, As I pest control around race horses...Skitty things at the best of times, I've taken down 9 birds with 11 shots on the farm, You just can't do that with a large report.. But also as a long range shooter and with a floating barrel you don't want anything too heavy giving you the pendulum effect from the barrel whip....But Jim is quite right, Unless you are making a moderator for a none FAC you are on very thin ice....

We have been doing a chunk of R&D on this for the UK market.... Great findings too. 

Be safe

Stig

Jim,

If I were to build an airgun moderators, I'd add a little glue and "permanently fix it" to the barrel. That should resolve any legal worries. 

Pyramid Air has an interesting article on the subject of airgun silencers. The potential risk is if you have (buy or make) a silencer that could be used on a firearm (a powder burner) and you do not have a permit, you could be breaking the law. At least that is the way I read it. So if you buy a DonnyFL (or other brand) for your airgun and the government wants to argue that it could be attached to a 22 rimfire, you could have an issue.

The little bit of research I've done indicate silencers for 22s use 1/2x28 threads. Airguns use 12x20 threads. That is probably to protect the suppliers of airgun silencers. My DonnyFL adapter uses 12x20 threads so that is what my silencers use.

In addition to having the wrong threads, the body of my silencers is schedule 40 PVC, That is rated for about 250 psi. It also won't take much temperature. I've bent it and changed the diameter with a heat gun to make dust collection fittings. That makes is not suitable for use on a 22 rimfire - or other powder burner, at least in my opinion. A commercial airgun moderator made of aluminum would not have these arguments.

Legally I don't think making it versus buying it changes anything. The issue arises if your airgun moderator could also be used on a rimfire or other powder burner. I don't think mine can and I certainly will never try them for that use. If I want a moderator for one of my powder burners I will apply for the permit and follow the law.

I am not trying to suggest that anybody using an airgun moderator in the U. S. is guilty of anything. I don't think we are. I am just saying that making it doesn't change anything versus buying it from what I can tell.

Another summary is that moderators or silencers are very clearly not legal for powder burning guns under U. S. law unless you apply for and are granted the necessary permits. The same law that says this is not applicable, by definition, to airguns. So the only issue I have seen postulated for airguns is if it is alleged that our airgun silencer can be used on a regulated rifle - powder burner. It seems to me that there is a defense for a plastic bodied airgun silencer that is not present for a metal bodied silencer but that is just my speculation.

I also do not have any powder burners threaded for a silencer and do not plan any. But if I were to get one, it won't have 1/2x20 threads.

JimD,

If you would like a legal view on the subject, United States of America Vs. Michael Crooker is well worth your time to read.

Thanks. Michael Crooker doesn't seem like a super nice guy but the fact that an appellant court reversed a conviction for a felon possessing a home made moderator based upon a lack of intent to put it on a firearm is interesting. It also was apparently made of metal and thus probably much more capable of working on a firearm than the devices I have made (which have a little metal but are mainly plastic with some wood).

The other reason I am fairly comfortable is the fact that moderators for airguns are widely available with no background check and are shipped through the mail. All this is inconsistent with anything legally a firearm. I can't see companies like Pyramid Air and Airguns of Arizona selling airgun moderators if they weren't pretty comfortable they were legal. Even shipping companies could have issues if they deliver a firearm without the appropriate paperwork. All these companies have apparently decided they are not legally firearms. (Legally a moderator for a powder burner (firearm) is considered to be a firearm - sounds funny but lots of legal stuff doesn't make a lot of sense). 

But I also understand there is plenty of room for other thoughts when there is no law or supreme court position that says airgun moderators are legal. The Alphabet org has apparently tried to apply firearms law to them based upon the concept that they could be used on a powder burner. But the Crooker court case even notes that a whole lot of things could be used in this fashion - even potentially a potato. So they did not accept that argument. Doesn't mean Alphabet org will not try again.

I promised some information on my home made moderators and finished the testing I plan for them a few minutes ago. I thought about starting a separate thread but I don't think this is significant enough for that. To recap a little, the first moderator I made was inspired by a youtube video and is made out of an old sprinkler. The insides are gutted and holes drilled in a plastic tube that runs the length of it. I bought a 1/2 NPT iron plug to drill and tap for 1/2x20 threads that are on the Donny FL adapter on my 25 caliber Avenger.

The other two were made of Schedule 40 PVC a little over 1.5 inches id with wooden end plugs made of 3/4 plywood to fit and an aluminum tube 5/8 OD and 3/8 ID running the length of the device. I drilled and tapped the tube for the same 1/2x20 threads.

The only one of these that does not clip the pellets throwing them way off target is the shortest, about 4 inches long. The sprinkler one is about 6 inches long and the other one of PVC started about 8 inches and got cut to 7 inches in an attempt to better align the tube to prevent the clipping. But that didn't work. The 4 inch doesn't seem to affect POI or accuracy at all but it was windy the day I was testing it so I'm not completely sure. I will probably mess with it some more before deciding. But the pellets at least hit the target in the area I am aiming and the groups look about right size, considering it was windy. I am mostly using pellets my Avenger doesn't like since I can't current buy more of the pellets it does like. I did shoot one 3 shot group with the "good" pellets and two were in one hole with the third about a quarter of an inch off. Usually they would all be in one hole it was windy and I don't always shoot at my best. So it is at least promising. 

I used a cheap $20 sound meter of unknown accuracy I bought from Amazon and placed it at 25 feet in front of my shooting position. I had it really close to my house for some of the measurements and that seemed to cause some of them to be louder than others. When I moved it 6 feet or so away the results stopped bouncing up and down. With those caveats it seems like the 4 inch drops the db by about 9 db. From 95.4db on average for the un-moderated but shrouded gun and about 86.4 db with the 4 inch moderator. The longer ones were a few db lower but they clip so it doesn't matter, they will be scrapped. 4 inch may too but if it really does not affect group size I might use it before getting a commercially made unit. I looked at some tests and I think they confirm my suspicion that this home made device is at best similar to the worst of the commercially available units and may be worse than any of them. The test I was looking at was a 22 caliber Avenger that tested at almost 105 db unmoderated. Two of the moderators they tested where higher than my little 4 inch but if you measured the db reduction they did more.

I did not spend a lot on this and I did get one moderator that might be worth using out of it. The key issue is getting the moderator aligned with the bore of the gun. I thought with a 3/8 ID tube I could align it well enough but mostly I did not. I think using a lathe to drill and tap the tube would do a lot better but I do not have a metal lathe. I used my drill press (including for the tap) and a machinist's vise but that did not align the threads well enough for the longer moderators.

I don't think I said it above but I used JB Weld epoxy to hold the PVC moderators together. It held up fine for the Avenger shooting it's current ~50 fpe tune.

I'm not trying to convince anybody to build something like this or not to. If you do it, be careful and whatever you do, do not try it or plan to try it on a firearm - a powder burner. That would be unsafe and illegal.