cw_3302 said:I shoot my 308 with a subsonic with my 220gr load dead quiet. I am stuck with the noise of the breaking the sound barrier. this is out in Washington state so I will trees along the edge of the range. The range is a bet over 400yr nice to load testing. right now working an a high flow ventilation system right now. Also does anyone what kind of lighting I need to have over my chronograph to make it work inside. thanks for some of your guy input
joshb said:Mass is your friend, coupled with vibration isolators. Years ago, I built a shooting range in my basement. I cast a 4 ft. X3 ft. Round Section of aluminum pipe into the concrete foundation at " shooting height".( standing pistol). From the foundation, I buried 80 ft. Of 6 ft. Corrugated steel culvert pipe out into the yard, with a 3ft vent pipe, at the end. The problem was, my shooting location was right under the kitchen sink. To deaden the sound (after extensive research) I built a room with double thickness drywall inside. Then I built another room inside that, with 2 more layers of drywall (mass) and a 1 in gap between all the walls and ceiling. (Vibration isolation) AND then another room inside that, same procedure.. The mass of the drywall and the gaps, did the job. I could shoot my 44 Magnum, right under my wife, while she was cooking, and she couldn't hear it ( if the TV was on). Outside, at the vent pipe, a bunch of bushes muffled the report to the level of a muffled clap. After 15 years and tens of thousands of rounds, I never had a problem, well, except that all my friends came to shoot my reloads. Of course, we down sized, sold that house, and moved into a smaller property. Thought about a new range, but here we have bedrock too high to make it feasable. I miss that house.
For it to work you must shoot the bullet sub sonic also . LarryI have tried sound absorption in a few contexts.
The the one that was most diligently pursued was a mainframe computer room. The method that worked best functioned by breaking up the sound wave reflections inside the room itself. We covered small (computer punch card) boxes with carpet swatches, and mounted them on the walls at random distances apart. It helped. The ceiling already had acoustic tiles, and the floor was off limits. At least we didn't have to shout at each other as much.
Another project involved an outdoor rifle range. We would bind several car tires (13" worked better) into cylinders, suspending them with their centers at bore height, and firing the rifle with the muzzle projecting partway into the center. The tire walls provided some baffling, and shot echoes were reduced.
One item to keep in mind... Wasps, etc., like to build nests when the range is deserted, and they can get mightily peeved when somebody touches off a shot several inches from those nests. Punch/cut drain holes in the bottom of each tire to prevent mosquito breeding.
Sound studios and music rooms can be acoustically isolated by building an acoustic wall. Separating two sills, and two headers by several inches, then putting up studs alternating between 2x4's and 2x6's provides at framework that can have fiberglass insulation woven from one end to the other in the gap between the two frames. Close the wall normally with dry wall on both sides. As long as there is no mechanical connection between the two frameworks (except fiberglass), sound transmission though the wall can be substantially reduced.
See if there might be some modified application of these tries to your project.
Greg
I shoot my 308 with a subsonic with my 220gr load dead quiet. I am stuck with the noise of the breaking the sound barrier. this is out in Washington state so I will trees along the edge of the range. The range is a bet over 400yr nice to load testing. right now working an a high flow ventilation system right now. Also does anyone what kind of lighting I need to have over my chronograph to make it work inside. thanks for some of your guy input
At 100 yards the bullet still sound the same as it did suppressed or not . LarryYears ago we had a range at school. Baffle system comprised of 55 gallon drums layed on their side with layers of insulation on the inside, and on the outside. Don't recall if it was two or three drums deep. The drums had those removable tops and the bottom was removed to put a removable top there also. They had a hole cut in the top so you had about 6-8" ring of metal on the top and bottom of the drum. You shot thru the middle of the drums. Most of the shot noise was contained in the barrels. The sonic boom was restricted by the half walls on either side of the shooting lane. You could hear the bullet smack into the bullet trap, but the folks in the welding shop upstairs could not hear the shooting.
Yes that will absolutely work, but you do t want to be breathing the little fibers that will forever be floatingThe cheap version is to cover with exposed fiberglass insulation (fibers exposed) covered loosely with chicken wire. The only down side is that just looking at the stuff makes me itch.