Energy to break house window?

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wyshadow

wyshadow

Member
May 11, 2015
1,696
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Las Cruces, New Mexico, United States
I take every precaution when it comes to shooting any of my guns, air or PB. When I shoot my pellet guns at home, I make sure I have a strong backstop to shoot into which is a 12 x 18 x 12 inch box made out of plywood stuffed with cloths and rags which is then backed with several sheets of plywood and a thick metal sheet sandwiched in between just in case a pellet bores a hole. On top of this I made another another 4 ft x 4 ft plywood stuffed with 2x4 and 2x6 wood which also has metal sheet sandwiched together. Behind this 4x4 barrier, I stacked a four foot high rock wall that run 20 feet along the fence which is located at the edge of our property which make up my 75 yard shooting range facing north. I'm not a paper puncher so most of the time I use my range to sight in my gun or to check my zeros or to test out a new pellet. After all of the precautionary steps I take, I still get very nervous when I shot my pellet guns at home. Our nearest neighbor is about a hundred yards from us but they are on the opposite side of my shooting range. I have one neighbor who is just north-east of my shooting range and they are about 110 yards from the house at my 2 o'clock position. They have a huge 8 foot rock wall that runs around there house which is very nice. This neighbor sometimes make me nervous when I shot on my range but its another neighbor that makes me very nervous because they are directly north of my shooting range but they are 170 yards away. I'm not sure if can call them my neighbor because they are actually in a different neighborhood. My 50 yard target also has rock wall I built and I'm less worried I will mess my target at this range. My 20 yard target is actually inside a smaller yard surround by a rock wall and this is where I mostly have been shooting my prod. If I some how missed my target, missed all my barriers, or I got a ricochet and my pellet some how made it to the house located 170 yards, would my prod's remaining 3 foot/pounds, or less if I got a ricochet, of energy break a window? Now I have to thank God this hasn't happened and I hardly shoot out to 75 yards. I got 3 foot/pounds at 170 yards for my prod with shrelok pro.
 
I take every precaution when it comes to shooting any of my guns, air or PB. When I shoot my pellet guns at home, I make sure I have a strong backstop to shoot into which is a 12 x 18 x 12 inch box made out of plywood stuffed with cloths and rags which is then backed with several sheets of plywood and a thick metal sheet sandwiched in between just in case a pellet bores a hole.

On top of this I made another another 4 ft x 4 ft plywood stuffed with 2×4 and 2×6 wood which also has metal sheet sandwiched together. Behind this 4×4 barrier, I stacked a four foot high rock wall that run 20 feet along the fence which is located at the edge of our property which make up my 75 yard shooting range facing north. I’m not a paper puncher so most of the time I use my range to sight in my gun or to check my zeros or to test out a new pellet.

fter all of the precautionary steps I take, I still get very nervous when I shot my pellet guns at home. Our nearest neighbor is about a hundred yards from us but they are on the opposite side of my shooting range. I have one neighbor who is just north-east of my shooting range and they are about 110 yards from the house at my 2 o’clock position. They have a huge 8 foot rock wall that runs around there house which is very nice.

This neighbor sometimes make me nervous when I shot on my range but its another neighbor that makes me very nervous because they are directly north of my shooting range but they are 170 yards away. I’m not sure if can call them my neighbor because they are actually in a different neighborhood. My 50 yard target also has rock wall I built and I’m less worried I will mess my target at this range. My 20 yard target is actually inside a smaller yard surround by a rock wall and this is where I mostly have been shooting my prod. 

If I some how missed my target, missed all my barriers, or I got a ricochet and my pellet some how made it to the house located 170 yards, would my prod’s remaining 3 foot/pounds, or less if I got a ricochet, of energy break a window? Now I have to thank God this hasn’t happened and I hardly shoot out to 75 yards. I got 3 foot/pounds at 170 yards for my prod with shrelok pro.
 
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I'm not a numbers and data specific individual myself. However I do know a little about glass. There are 2 different types of "breakage" when talking about breaking glass from impact. There is breakage from bending or applying pressure to the glass by pushing on it until it causes enough stress to break or fracture. This refers to the tensile strength of glass. Typical breakage of this type would be by a person or large object falling against or being thrown, or even wind blowing, against a fairly large pane of glass. The tensile strength of tempered safety glass is typically 4 to 5 times greater than normal glass of similar thickness. 
The other which is of more interest and pertinent to this topic is what we can refer to as mechanical strength. Ie: what is the impact velocity required to break glass. As a rule of thumb a .25 (1/4") diameter object (pellet / bb / rock ...) weighing 77 grains and traveling at 60 fps will typically cause tempered glass to break (shatter). For normal annealed glass the velocity required is about 1/2 that of tempered glass. 30 fps for the same "object". Interestingly enough this amounts to tempered glass having about 4 - 5 times higher impact resistance over annealed glass.
This is all wonderful in the world of theory and empirical scientific application of known and given data. But glass is considered a liquid due to it's molecular structure even though it is "solid" at normal temperatures. Because of this it is prone to defects and impurities that can cause it to deviate from all of the know properties listed above and cause unforgettable (many times regrettable) things to happen at the most inopportune times. For this reason alone I would refrain from shooting in any direction where there is a reasonable chance of hitting any kinds of windows.
All we really want to know is will the gun / pellet combo we are shooting at such and such a distance possibly break my neighbors window on their house or car. An interesting topic. I might have to start saving the various windows that I replace due to failure and start shooting them with my air guns at various distances, record and share the results. Could make for an interesting video or 2. After all who doesn't like to see and hear smashing / shattering glass.
 
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"glassman"I'm not a numbers and data specific individual myself. However I do know a little about glass. There are 2 different types of "breakage" when talking about breaking glass from impact. There is breakage from bending or applying pressure to the glass by pushing on it until it causes enough stress to break or fracture. This refers to the tensile strength of glass. Typical breakage of this type would be by a person or large object falling against or being thrown, or even wind blowing, against a fairly large pane of glass. The tensile strength of tempered safety glass is typically 4 to 5 times greater than normal glass of similar thickness. 
The other which is of more interest and pertinent to this topic is what we can refer to as mechanical strength. Ie: what is the impact velocity required to break glass. As a rule of thumb a .25 (1/4") diameter object (pellet / bb / rock ...) weighing 77 grains and traveling at 60 fps will typically cause tempered glass to break (shatter). For normal annealed glass the velocity required is about 1/2 that of tempered glass. 30 fps for the same "object". Interestingly enough this amounts to tempered glass having about 4 - 5 times higher impact resistance over annealed glass.
This is all wonderful in the world of theory and empirical scientific application of known and given data. But glass is considered a liquid due to it's molecular structure even though it is "solid" at normal temperatures. Because of this it is prone to defects and impurities that can cause it to deviate from all of the know properties listed above and cause unforgettable (many times regrettable) things to happen at the most inopportune times. For this reason alone I would refrain from shooting in any direction where there is a reasonable chance of hitting any kinds of windows.
All we really want to know is will the gun / pellet combo we are shooting at such and such a distance possibly break my neighbors window on their house or car. An interesting topic. I might have to start saving the various windows that I replace due to failure and start shooting them with my air guns at various distances, record and share the results. Could make for an interesting video or 2. After all who doesn't like to see and hear smashing / shattering glass.
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That would be sweet if you did that video. I've seen glass brake from a slight touch, and not break from my hammer glancing it9annealed not tempered). It is a finicky beast.
 
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