Not a bunch of swings.

I'm not starting a mosquito breeding program.

I'm not going in the Huarache manufacturing business.

Right column is 6' high. Left column is 5'6" high.

Paul

DAMIFINO.  .....Paul h

A 'silencer'.

Paul

I've heard of using tires for that. Kinda makes a rifle barrel heavy tho.

RJ

I haven't figured out how to attach it to the barrel yet...

Paul

Have you heard of super glue & duct tape? Redneck  fix for most anything that needs fixing.   .......Paul H:

Paul, that's an excellent idea. Our Fish & Wildlife department built us a shooting range about 6 miles from where I live with four or five shooting "tubes" made from about 24 inch galvanized culvert corrugated drain pipes about 30 feet long. They do a pretty good job of muffling sound but they're eardrum busters when you're shooting thru them at your target. Hearing protectors help a lot. They're sloped down a bit at the exit end & powder fumes drift back in your face. Black powder smoke makes life miserable. The rubber should  deaden sound much better than the corrugated metal does. Two "rails" parallel to each other should make a good platform for the tires. 2x4's around 12-16 feet long should work. You'll need a cover over the front with a 12x12 inch window cut in it to cut down on back blast & noise. .....I really like the idea.  ......Paul H

I intend to put "pink" fiberglass insulation in the tires, Paul. And I MAY keep that in place with chickenwire. Not sure whether the chicken wire will be necessary, but I suspect so. I saw a Youtube video in which the "backblast" was significant, and I have heard others speak to that issue as well.

The culvert seems like a good idea, but I'm a little surprized they didn't spray the inside with at least a thin layer of polyurethane insulation. Some on the outside would help as well. 30 feet is pretty long! The Swiss have started making "things" specifically for this purpose. They are triangular tubes about 6 feet long made of special (= expensive) sound-absorbing panels. For standing, the tubes are elongated "up and down". There is one guy on Youtube https://www.youtube.com/watch?v=HQ9nd6p_9Y4 that uses a plastic drum and it's pretty effective.

I'll be making the frame today. 2x6 "X" with 2x4 or 2x6 'stringers' holding the Xs together and providing the support for the tires. The tires will be screwed together at the bead with 3" decking screws. The shooting bench table is 29" off the ground so the design of the frame will put the lower edge of the ID of the tires at 30". I think I am going to make them in 4-tire units. First, for ease of handling, and second, so I can fiddle with the configuration ("large" and "small" diameter tires), to see what provides the best sound abatement. (Truth be told, I don't think it will matter much how they're configured.) Large (2" at least) holes will be cut in the bottom of each tire to allow water to drain out. At the moment, that's about all there is to the 'design'.

Paul

Today I built the frames for the first two sections. The first section holds five of the 'small' tires, and the second section is four 'large' tires. A little math to get the design started, and then 'hand' fitting the rest. Total length of the two sections is 7 feet. I think the other two sections - one of 'small' tires and one of 'large' tires - will in fact increase noise reduction. There was more to the construction than I anticipated. Lots of 'wrestling'.

Here are pictures.

The first 5 small tires looking through the 'tunnel'.


The first 5 from the side:


Here are all 9 from the side:


And here are all 9 looking through the tunnel:


Finally, the drainage holes. (Phone camera and didn't know the picture was out of focus.)


The drainage holes were more difficult to cut than I thought they would be. I anticipated the "wires", but I didn't figure on the rubber expanding as it got hot.

Screwing the beads together didn't work because the sheetrock screws couldn't hold against the tension. They pulled out. However, I'm not sure that leaving the tires unattached to each other is 'bad'. They're not bad to 'man-handle' onto the frames, and doing so would allow some flexibility. Also, they 'snug up' very easily and do not have a tendency to tip over. BUT... the muzzle blast MAY cause some unacceptable movement if they are not attached to one another. To tell the truth, a rope tied around them (through the 'tunnel') would probably be just fine.

I need to get the insulation and chickenwire. Also, the 19" hole is pretty big. I think covering the 'entrance' except for enough opening to allow seeing through the scope and for barrel/bullet clearance will be both necessary and beneficial to noise reduction. It might help to cover the distal end of the tunnel too, but I think that might make setup (aligning with targets), more trouble than it's worth. I think what I might do for the proximal opening is to make two plywood panels, one for each side, leaving a space of 4 to 6 inches between them. Then a panel that comes down from the top, that is adjustable so that it can be locked at a height that the shooter chooses. This would minimize the opening through which 'blowback' could come.

Paul

Banding the tyres together might work. Reducing the input aperture might also save ears a little.

Looking good. Paul but the framework is much more complex than I would make it. Two parallel 2x6's spaced just far enough apart to allow the tires to sit between them would work. The tires would have to have the same approximate outside diameter. I definitely wouldn't put Styrofoam in them. The setup you have is much like the Lybrinth seals used in jet & turbine engines on rotating shafts to reduce or stop oil from leaking around rotating shafts. It will do the same for sound or anything else passing thru the fins. Lybrinth seals work on the principal  of reducing pressure as it goes from one fin to the next until there is  no more pressure. The same thing happens with sound. If you fill the tires with Styrofoam, you're back to a solid tube again. Might as well use a large pipe. It's the "fins" in the setup that reduce noise. Unlike solid material, the rubber will absorb sound too instead of letting it bounce off. You can tie the tires together by running wire through the "tunnel: & around the outside & tying it. One on each side will work. .......Paul H

I might add that a bit of oil on the hole saw keeps the rubber from sticking to the saw as it gets hot. ......Paul H

I would bungee them together.  To each other at the top at 12:00 and also to the base where they rest on the 2x6s at the bottom.
Put screw eyes in the frame to hook them to.
Easy on/easy off/ easy adjust

Get the bulk cut-to-length stuff at ACE Hardware and a few hooks.

More unwanted advice for you, Paul. If you're bent on adding Styrofoam to the inside of the tires, you might consider the foam insulation that comes in pressurized cans. It will stick to the inside of the tires & prevent drainage if water should get in the tires. You could put peanut Styrofoam in the tires & squirt foam insulation in with it. At any rate filling the tires with anything defeats the "baffles"  created by the sides of the tires. I went down to the game department range & took a few pictures of their setup. I thought the tubes were corrugated pipe. They are not. It's 1/4 inch thick steel pipe. Stainless steel electric fence wire for tying the tires together won't rust away or deteriorate. Galvanized wire does. ......Paul H.....Well, I have no idea where the pictures went. I'll try again.  ....ph....

Paul - Never unwanted advice from anyone at THL (that's largely why I post these "Make it" threads), and especially not from you!

You've misinterpreted my "insulation". I intend to use FIBERGLASS insulation. NOT rigid foam!

"Of course the tires would have to be the same outside diameter" sounds "easy" but it isn't. In those tires you see in the above pictures, I have two sets, each of which came from the same vehicle, and even those are not the same OD! Forget brands!

This isn't a 'permanent' set up. The 'shooting range' is not my property, and consequently, it needs a certain level of portability. Hence the over-built frames.

Jaimie.270 - I wuz thinkin' the same thing!

Paul