Tube Range
- Thread starter Terry
- Start date
If you mean a tunnel, Karl Feldkamp had one 100 yards long at his gun shop or house near Detroit, but he sold out and moved to Idaho. I don't know if he reads these forums or not. I also don't know if Jim McClellan, who worked for him, got a chance to shoot in the tunnel or not. If they read this maybe they will chime in.
Corbon in Sturgis has one… likely their tech guys can answer any questions you might have. FWIW, I've used it… oddly enough mirage can be an issue. 
I'm building one at the moment. Not much design info around on them. The only person I could find who had any experience with them was the Engineer who wrote the NRA range design manual. I had a bit of email correspondence with him about minimum size pipe to use. He advised that it should be at least 18" diameter and to watch out for flashback from unburnt powder residue.
There is a good article in the Winter 2002 edition of Small Caliber news by Frank Tirrel about evaluating zero condition in which he mentions about a 100m pipe range he build. He also mention about mirage and solved it be putting in a fan to force air down the pipe. He built it using 4 foot (1.2m) diameter conc pipe.
That would be great, but 4 foot conc pipes here in New Zealand are about $300/m!
In the end I settled on 2 foot (600mm) diam pipe. Even pvc farm culvert pipe is $130/m so that $13k for a 100m, I thought about using 44gal steel drums and the equivalent plastic ones, but they are slightly smaller Id when you leave a bit of meat around the rim to give then some regidity.
Finally stumbled on the idea of using HVAC helical light gauge galv steel ducting. They are not very rigid, but I only intend to bury it enough to deaden the sound, so figured I might get away with these if I'm careful with backfilling around.
The 2 foot diam ducting is costing me $50/m so I put 12m in the ground and did some test shooting. Definitely has potential, but dust and smoke could be an issue as the blast stirs up any dust in the pipe, and the smoke takes awhile to clear.
I've now got 50m in the ground and am going to build an expansion chamber so I can do some further testing to iron out any issues before I take it out to 100m. This expansion chamber will eventually be used to hold a target and bullet catcher at the 50m mark
Cheers
Grant
There is a good article in the Winter 2002 edition of Small Caliber news by Frank Tirrel about evaluating zero condition in which he mentions about a 100m pipe range he build. He also mention about mirage and solved it be putting in a fan to force air down the pipe. He built it using 4 foot (1.2m) diameter conc pipe.
That would be great, but 4 foot conc pipes here in New Zealand are about $300/m!
In the end I settled on 2 foot (600mm) diam pipe. Even pvc farm culvert pipe is $130/m so that $13k for a 100m, I thought about using 44gal steel drums and the equivalent plastic ones, but they are slightly smaller Id when you leave a bit of meat around the rim to give then some regidity.
Finally stumbled on the idea of using HVAC helical light gauge galv steel ducting. They are not very rigid, but I only intend to bury it enough to deaden the sound, so figured I might get away with these if I'm careful with backfilling around.
The 2 foot diam ducting is costing me $50/m so I put 12m in the ground and did some test shooting. Definitely has potential, but dust and smoke could be an issue as the blast stirs up any dust in the pipe, and the smoke takes awhile to clear.
I've now got 50m in the ground and am going to build an expansion chamber so I can do some further testing to iron out any issues before I take it out to 100m. This expansion chamber will eventually be used to hold a target and bullet catcher at the 50m mark
Cheers
Grant
joshb
Gold $$ Contributor
I used corrugated steel road culvert pipe. 5 ft diameter. Can't imagine what it costs On your Island. Pretty cheep up here. Have you thought about just digging a ditch and covering it with a tarp? Farmers up here use clear sheet plastic over a frame for potted plant production. Might work. Good luck.
BoydAllen
Gold $$ Contributor
Years back, I did some research on tunnel designs and problems. The subject is a lot more complex than meets the eye. There are a number of tunnels that are owned by companies clubs, and individuals. Rushing in, without the proper engineering is likely to result in the creation of a very expensive "monument" that does not work as well as it could have, and cannot be easily fixed. This is particularly true if you plan on using one to test rifles that are shot off of sand bags, that have to be re-aimed for each shot. Mirage is the issue. Any time that you have a surface that is warmer than the air next to it, mirage can and will happen, and it will move the target image, so that you will be shooting at different target locations from shot to shot. Fellows who lack experience with the sort of high magnification scopes that are required for competitive benchrest shooting will not properly understand this issue, so it will be easy for them to overlook it in the design stage. I have a friend who has a state of the art tunnel that has been used to test bullet designs. He is in the construction business, and it was still very expensive to build. It is underground, made of concrete (with a smooth tube interior, and features a large expansion chamber in front of the tunnel, as well as proper control of ventilation so that the target image is stable. It has been a while since I discussed it with him. I think that I will give him a call and ask him what he thinks it would cost to reproduce today. If I manage to get that done, I will post the information on this thread.
Added a little later: We are talking a half million to construct, a thousand a month in energy costs to keep the air conditioned to the proper temperature, and a lot of vacuuming to keep the unburned powder cleaned up. Unless you are using one a lot he said that it would not be worth it. You might look into what Bart Sauter of Bart's bullets has. I believe that he dug a trench, formed and poured the sides, and shoots out of his basement. My friend told me that if he were to shut down his conditioning system that it would take a month to bring the tunnel back to a stable temperature condition needed for critical work.
Added a little later: We are talking a half million to construct, a thousand a month in energy costs to keep the air conditioned to the proper temperature, and a lot of vacuuming to keep the unburned powder cleaned up. Unless you are using one a lot he said that it would not be worth it. You might look into what Bart Sauter of Bart's bullets has. I believe that he dug a trench, formed and poured the sides, and shoots out of his basement. My friend told me that if he were to shut down his conditioning system that it would take a month to bring the tunnel back to a stable temperature condition needed for critical work.
bOYD, All good points to consider. Thats the reason I have used "cheap" materials and only built 50m so I can test it and find out some of the pitfalls. Not sure how much of an issue mirage will be. I'm in a reasonably moderate climate in Tauranga NZ. I'm hoping a simple fan to pull air out from the middle will create enough air change to keep mirage to a manageable level....time will tell.
BoydAllen
Gold $$ Contributor
My friend's tunnel is set up to pull air at the far end. I believe that this is pretty much standard practice. If you don't want to be dusting things with lead, or breathing it, if you are recirculating air, some filtration of the exhaust is called for. A local range uses two layer of 40% pleated paper filters, which get burned when they are changed, and the lead recycled, to deal with any hazmat disposal issues.
JRS said:
Dont tell dont ask
joshb
Gold $$ Contributor
When I built mine, I met with the Township and building inspector. They said that there was nothing on the books or in the codes about shooting range requirements, so I could do whatever I wanted. The inspector asked if he could come use it when I was done. I had a lot of fun with that range and a lot of people used it.
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