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> Rifle barrel lying in the sun?
Rifle barrel lying in the sun?
@ 06:07 am (GMT) |
Warwick MarflittSo what happens when you're sitting in the sun glassing the clearings looking for Deer and the Suns heating one side of the barrel? I like to cover the barrel to stop this happening as one side ends up being hotter than the other? Am I being to cautious? I just put my jacket over the barrel until I see Bambi. My thoughts for doing this is that as things get hot they expand and I think the hot side will be applying force against the cool side. I guess that some testing wouldn't be hard to do and see how it effects the point of impact? All and any thoughts you have about this would be appreciated. |
Replies
@ 02:47 pm (GMT) |
Paul LevermanRe: Rifle barrel lying in the sun?It's been a very long time since the days of thermodynamic studies, but yes, there will be changes.I don't believe that the "force against the cool side" is relevant, as this is a thermal stress and not a mechanical stress. The concern might be in the fact that as materials increase their ambient temperature, they decrease in density. Steel will increase its size by approximately 6.5 X 0.000004" per inch of material. With the changes in density and physical size, harmonics could very well undergo a nodal change, but would it be significant? And if it did change, my thoughts would be that it would increase (or possibly decrease) group size, so really all that would change would be the range at which ethical hunting should be limited to. I have to go now. My brain hurts. |
@ 04:13 pm (GMT) |
Bryan WebsterRe: Rifle barrel lying in the sun?There you go Warwick. A good experiment to try out.I suspect there will be a nearly immeasurable impact change unless your rifle is loaded and the ammunition in the chamber and/or magazine has been affected by the heat. In this case there would be an increase in pressure and a small change in point of impact. This might be of some help: CHANGE in UP FROM ZERO given an example of 59 Degrees F or whatever the temperature was when you were sighting in +30 Degrees or more 300M -2.0 MOA 600M -3.0 MOA 1000m -4.0 MOA +20 Degrees 300M -1.0 MOA 600M -1.5 MOA 1000m -2.0 MOA -20 Degrees 300M +1.0 MOA 600M + 1.5 MOA 1000m + 2.0 MOA -30 Degrees 300M +2.0 MOA 600M +3.0 MOA 1000m +4.0 MOA |
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@ 05:12 pm (GMT) |
Bryan WebsterRe: Rifle barrel lying in the sun?Here is an article on the topic from your country:http://longrangeshooter.com/2009/02/temperature-effects-on-zero/ |
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@ 07:56 pm (GMT) |
Warwick MarflittRe: Rifle barrel lying in the sun?Thanks Bryan. I'm not Australian! The greatest insult ever! Is to call a Kiwi an Australian!!!!! Being gut shot would be less painful!!! Barometric pressure and humidity weren't measured? and are never going to be the same. and the +\- accuracy of the test equipment leaves gaps in the testing. They did see a change in point of impact so there's something going on! Food for thought though. Thanks for finding and sharing the article. All info is good info. |
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@ 08:00 pm (GMT) |
Warwick MarflittRe: Rifle barrel lying in the sun?If everything was the same and one side of the barrel was hotter than the other is what I was wondering about. Why does the roof on a house creak as the sun shines on it in the morning? |
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@ 04:33 am (GMT) |
Paul LevermanRe: Rifle barrel lying in the sun?I'm thinking that if your rifle is built to the same exacting standards as your roof, your roof shouldn't creak. However, with a multitude of different densities of materials that make up the roof, all with their own expansion factors, it's a wonder it's still on the house. The nails are loose, the house and trusses are not square or plumb, it's full of holes. Your rifle is all steel in the barrel, is bedded with a compound that expands at the same rate as the steel, and it only has one hole in it. |
@ 09:13 pm (GMT) |
Nathan FosterRe: Rifle barrel lying in the sun?I remember once we were rolling structural bar steel for a silo. I think it was 6 metre diameter. We then let the rolled bar sit half in the workshop and half out the door. The half that was out the door began to lose its radius in the sun.In this instance, we had induced stress into the steel. So that would be the first element. The less stress we have in the steel to begin with the better. Length also comes into play. The longer the piece of steel, the more it will sag. There will always be some element that effects the barrel steel and the exact point of impact of shots, not just exterior ballistic elements. The best we can do is minimize this. In your example Warwick, you could simply lie the rifle on its left side for a time, then roll it over to its right side- if you really wanted to get finickity about it. |
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@ 11:27 pm (GMT) |
Warwick MarflittRe: Rifle barrel lying in the sun?Thanks Nathan . There's nothing finicky about rolling in the sun haha! Hot water will expand a wheel bearing hub enough to allow the bearing cup to slip in with your fingers and no punches n hammers to knock it in? Put the bearing cup in the freezer and it will fall into the hub! The old guy's I learnt my trade from taught lots of handy tricks to the young guy's who wanted to learn. There's 200 years of knowledge stored in the heads of 5 men with 40 years experience? All you need to access it is watch, listen and do what they say and getting their smoko (morning tea)helps too! |
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@ 03:13 pm (GMT) |
Bryan WebsterRe: Rifle barrel lying in the sun?Quote: Thanks Bryan. I'm not Australian! The greatest insult ever! Is to call a Kiwi an Australian!!!!! Being gut shot would be less painful!!! Barometric pressure and humidity weren't measured? and are never going to be the same. and the +\- accuracy of the test equipment leaves gaps in the testing. They did see a change in point of impact so there's something going on! Food for thought though. Thanks for finding and sharing the article. All info is good info.
I do not normally take shots out really far at game, but on targets it is instructional. When doing that I use a ballistics program on my iPhone that takes into consideration wind, temperature, humidity and a pile more stuff. It really does work, but I prefer to stalk game once spotted and get to within at least 400 yards or so or preferably a whole lot closer. Fortunately a lot of our country here allows for this. Having shot a lot in the mountains here, I have never felt the need to not try to stalk closer. Sorry Warwick about the error on your location! ha ha. |
@ 09:07 pm (GMT) |
Shawn BevinsRe: Rifle barrel lying in the sun?Having welded and set more than a few bridge girders, I can tell you heat changes the equation on everything. Steel being a pretty good conductor with equalize pretty quick in the ambient temperatures. Will the gun barrel steel disperse the heat quickly? A laser thermometer could tell you pretty quick how much of a difference there is between one side of the barrel vs another.Interesting. |
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