Foot Lbs verses roof damage ?s
- Thread starter igolfat8
- Start date
Hi Tim
If you do find the soltution for current conditions, doesn't the fiberglass become more brittle with age, sunlight and heat?
A brand new fiberglass sheet might be able to take the impact,
but after a summer or 2..you might be cracking the roof instead of putting holes.
I am just guessing, but i am thinking that you will not be able to shoot inside there in the near future without risk of damage
If you do find the soltution for current conditions, doesn't the fiberglass become more brittle with age, sunlight and heat?
A brand new fiberglass sheet might be able to take the impact,
but after a summer or 2..you might be cracking the roof instead of putting holes.
I am just guessing, but i am thinking that you will not be able to shoot inside there in the near future without risk of damage
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You might be right Mike? Life sure was a lot simpler when he had steel roofing on his barns.
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You may want to ask your client if they have any remnants of the fiberglass left over from the installation.
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What slows down the GTO's is not their light weight per se, but their low BC.
There is a whole slew of low BC pellets, generally wadcutters and those hollow points that try to double as ashtrays.
Here is a link for a list of BC numbers.*
But low BC means not just they slow down quickly, it also means they suffer from more wind drift.
And your barn fans are your enemy — 40 yard shots give the artificial wind ample opportunity to mess with a low BC projectile....
Your particular shooting scenario is both a terminal ballistic AND an external ballistic challenge! Fascinating!
If I was committed to solving this, here's what I'd do:
🅐 I'd choose .177 caliber:
As the lighter weight (c. 7gr vs. 14gr) permits higher velocities (to prevent flyers) at lower energy levels (and energy is in the end what pushed the pellet through the roof):
7gr at 600fps = 5.6FPE
14gr at 600fps = 11.2FPE
Yes, the larger impact surface distributes the destructive power on a larger surface, but the .22cal has almost twice the energy.
🅑 I'd test the many variations of domes in .177 that have a relatively high BC in .177:
Which of these have sufficient precision in my gun at 40y?
And at how low of a velocity can I maintain that precision?
🅒 I'd contact the roofing company that installed the roof and kindly ask them to provide you with some pieces of the fiberglass — or to forward a nicely formulated email from you to past clients with the same roof.
🅓 Once obtained the fiberglass, I'd to test shots at different angles, since a 90⁰ angle of impact will be the worst, but already at 45⁰ you'd have a lot less force on the fiberglass.
🅔 If the .177cal pellets don't prove satisfactory — either because of too many flyers, or because the still break the fiberglass at low velocities — you can always try the same tests with low weight .22cal domes.
Your exploits of killing (a felt) 10% of the world's feral pigeon population — are legendary. You are one of my pesting heroes of all times.
All the best to you and your team mate!
Matthias
*Link:
Ballistic Coefficients
Hard Air Magazine is publishing the World’s first comprehensive, structured and independent list of airgun pellet Ballistic Coefficients.
hardairmagazine.com Last edited:
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Thanks for the suggestions @JungleShooter (Matthias). Our average upward shooting angle that we use on our dope charts is 35* and the fiberglass roofing is corrugated so on a rare miss the pellet is actually hitting the corrugated ribs closer to a perpendicular angle instead of a lower angle glancing blow.
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I've never heard of a dairy using fiberglass roofing on there barns. I can't imagine they would hold up too great but I guess they won't rust out....id try .177 slow and see. Or GTOs. I use my barn gun around 12fpe in .22 or a HW30S which is around 620fps with a 8.4gr and have no issues unless the tin is real rusted. Then again I'm shooting close range say 5-15yds and it's going through the bird first so slows it down good also. But fiberglass? That's very interesting
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I would try some different pellets that work well at lower speeds . There are tons of pellet guns shooting .22 in the 400-600 fps zone with accuracy.
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I wonder what type of lead free pellets would work. Higher speed lower weight. Or if a plastic projectile would work. Faster than airsoft but still accurate and hard hitting enough to kill. Maybe just reduce the range to where a lower ftlb is still accurate.
Allen
Allen
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This is a large industrial dairy. They milk 15,000 head plus they have breeding and birthing barns as well as an automated merry-go-round milk house. Each barn is a 1/4 mile long and they have 6 barns with plans to expand again this year. Its a massive operation, at least in our rural area. They used to have steel roofs on the barns but those rusted out and the Amish replaced them two years ago with fiberglass. It certainly lets in a lot more light but the downside is we have to really be cautious of our shot placement and backstops. We are not shooting willy-nilly in there but misses do happen upon occasion.
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This was my first thought as well, is it really fiberglass panels or is it polycarbonate panels? They look the same but are not. Polycarbonate is much more durable, I used it on my wife's hobby greenhouse.
I'll check to see if I have some scrap poloycarbonate pieces in my shed. I still stand by my comment there is nothing that can be done to limit the size/weight of pallet or by reducing the fps and still have the power to take out the pest(s).
I'll shoot a few tests and give you my findings, give me a day or two.....Always exciting to shoot stuff up. LOL
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Thanks @WoodWelder . I'll look forward to your results.
You can see pictures of the roof in this thread. Perhaps you can identify the material?
www.airgunnation.com
You can see pictures of the roof in this thread. Perhaps you can identify the material?
Set a new world record today 306 … and shattered that record again 451 and AGAIN ... 540!
Well … take that with a grain-o-salt. My buddy and I have been hunting a large industrialized dairy farm permission for several years trying to reduce the pigeon population. We’ve shot over 6,000 pigeons there. The owner was so sick of the birds he went to great expense to enclose all of the...
www.airgunnation.com Upvote 0
Lol wow that is a big place. We only milk around 800 cows. We got some big places by us but only max out around 5-7k milking. It's very interesting to me to see a place that large not have lockups for the cows. Anyways besides the point, yeah I can see why shooting there would be more difficult now. Again lighting is real nice but poking holes is I'm assuming quite a bit easier. We have open lots here so most my shooting is outdoors, no worries for hitting tin. My Evol is setup for in our milking parlor pigeons roost in the rafters and I don't shoot much there as there isn't much down time so maybe once or twice a month I will shoot 5-10 when I have a few min. Then again my dad and I have drastically reduced numbers on our dairy the last few months. Where we had maybe 250 pigeons I'd say close to 75 now. You shooting hundreds in a day and so many still is mind boggling but that big of a place does make sense
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Are “Lock Ups” those pipes that hold the cows head in place when they stick their head through it? If so, they do have those in the barn that has the pregnant cows In it.
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