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June 11, 2016, 12:12 PM | #51 |
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It is all a compromise.
Gravity is a constant, so "Flat Shooting" is all about velocity. In reality, it is not that important at normal hunting ranges. Zero your rifle at 200, and hold high a bit at 300, or you can adjust your scope. How much you hold off with one cartridge vs another is really irrelevant, provided you know the number for the rifle you are shooting (~7.5" for the .30-06, ~6" for the 270). Where "Flat Shooting" is a benefit is when you get the range call wrong, but in reality, at reasonable hunting ranges, it is not enough to matter. If you think Bambi is at 300 yards, and he is actually at 325, a 150gr .30-06 will be ~3 inches low. A "flat shooting" 130gr .270, in the same situation will be ~2.5 inches low. At longer ranges, you call the range 500 yards and it is really 525, the .270 will be 5.6" low, the .30-06 will be 7.7" low. Assuming a perfect hold and shot, both would probably still hit, but neither would be a good hit, most likely. Most people have no business shooting that far anyway. Keep in mind too, that drag is based on the square of the velocity, so higher velocity bullets shed speed quicker the faster you drive them. For example, even a bullet with a pretty good BC, for example the Hornady 6.5mm 140gr Extremely Low Drag Match (0.610 G1 BC), if you somehow were able to launch it at 4000 fps, it would lose ~175fps in the first hundred yards. At a more realistic but still fast 3000fps it loses ~160fps in the first 100 yards, and a pretty slow 2000fps it drops ~128fps. If the bullet sucks ballisticly, for example the .17cal 20gr Hornady VMAX (0.185 G1 BC), from a .17 Remington at 4000fps loses 638 FPS in the first 100 yards. You also haven't mentioned sectional density, witch for a given caliber increases with bullet weight. In other words, for most North American hunting, as long as the cartridge is of adequate power, and you use an appropriate bullet, any of them will work fine, and if you do your part, Bambi won't know that he was hit with a 90 gr .243, 140gr 6.5 Creedmoor, 130 gr .270, 180 gr .30-06, or a 200gr 8mm Mauser, or anything in between. So in other words, here are most of the things you need to balance when deciding on a cartridge. Sectional density Velocity Energy Ballistic Coefficient Barrel life Recoil Cartridge OAL (short/long action) Ammo/component availability If I was shopping for a general purpose, sporter weight hunting rifle, I would probably look for a 6.5 Creedmoor. The .264" 140gr is a sweet spot for all of the above except ammo availability (you probably aren't going to find it on the shelf at WalMart), but reloading components are readily available. With the 140 gr hunting bullets (Sierra GameKing, Hornady Interlock, etc) it is fine for anything in the lower 48 short of big bears, and I wouldn't hunt those anyway. There are also light (<100gr) varmint bullets available. |
June 11, 2016, 01:19 PM | #52 |
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Since we know the bullet starts dropping as soon as it leaves the barrel, we pick a point where we want the rifle zeroed.
If we are shooting closer or farther, we will either be low or high. So somebody, a long time ago made little knobs for our sights so we can adjust, and be dead on for what ever range we want to shoot. In reading these post, I see people say a bullet from a X cal. will drop a certain amount at a given range where a Y cal bullet will drop +/- more or less then bullet Y. Maybe so, in a vacuum. I don't shoot in a vacuum but I do know its more then cal. that makes a bullet drop more or less then another bullet. There is such a thing called ballistic inequality. Meaning some bullets pass through the air better then others. I just picked up my Lyman Reloading guide and turned to 30 cal bullets. Just off hand I picked 200 gr bullets. One has a BC of .481, another has a BC of .565. Everything else being equal the higher BC bullets will have less drop then the lower BC bullets. Why? Because we cant shoot in a vacuum, we have air the bullet needs to pass through, which tends to slow down the bullet via drag. We know if you drop two objects straight down, they will hit the ground at the same time. If barrel is level, it will hit the ground at the same time as one dropped straight down if dropped from the same height. The difference is the bullet will drop a ways from the barrel. The higher the BC the farther from the barrel it will drop. Its been said, that the best sniper is the one with the best gun, fastest bullet, and best scope. I don't agree with that, I contend that the best sniper is the one who learns to weaponized math. In other words, learning you rifle, your ammo and what the environment does to the bullet from that rifle in flight. You can compensate for a slower bullet, by making a few more clicks on your sights. You can choose a bullet that is designed to work at the distance of your target.
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June 11, 2016, 05:14 PM | #53 | |
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If you have two rifles, both with a 1.5" scope height and a 200 yard zero, one in .270 shooting a 130 grain Spitzer Boattail GameKing at 3200FPS, and the other a .30-06 shooting a 150 grain Spitzer Boattail GameKing at 2900 FPS, the .270 trajectory will absolutely be "flatter". The .30-06 will have a higher apogee before the zero range (about .4 of an inch at 125 yards), and drop off faster after the zero range, about 2" lower at 300. This is entirely due to velocity and flight time. The .30-06 takes longer to reach the target, and is effected by gravity longer, so it drops more. In this case, the .270 has a higher muzzle velocity and a higher BC. My point is that in the grand scheme of things for a hunting rifle, the difference between a "flat shooting" .270 and a non-flat shooting .30-06 is not really enough to care about when choosing a medium game cartridge. As long as you know your rifle and where it shoots at a given range, "flat shooting" just doesn't matter. |
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June 11, 2016, 07:21 PM | #54 |
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Gravity is a constant. The acceleration due to gravity on Earth is 9.8 m/s squared and that's how it is with all objects regardless if the object is heavy or light. If the Earth didn't have an atmosphere you could drop a small rock and a large rock at the same time and they would both hit the ground at the same time. The rate of fall would be the same for both rocks 9.8 m/s squared. Supposedly they did that experiment on the moon which is in a vacuum. The difference here on Earth is that Earth does have an atmosphere and that will slow the rate of fall since the rocks would have to push the air aside as they're falling towards the ground.
When you plug in the equation F=MA (Force = Mass times Acceleration) the larger more massive rock will fall with more force than the smaller rock and thus it will push the air aside faster and fall faster. Now, as with bullets if you apply that same principle a bigger bullet will fall faster. A bullet of more grains will fall faster and thus its trajectory will be more of an arc. Also it will not go as far since it will hit the ground sooner. So a lighter faster bullet will not only have a more flat trajectory it will also go further. Now, I never got far enough in Physics to understand about how drag affects velocity and how its the velocity squared that's lost when it comes to drag but that would be another fascinating topic of discussion and something else to take in as a factor. |
June 11, 2016, 08:10 PM | #55 | ||||||
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Mythbusters confirmed this with a .45 ACP one episode: https://www.youtube.com/watch?v=D9wQVIEdKh8 Quote:
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http://www.jbmballistics.com |
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June 11, 2016, 10:54 PM | #56 | |
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June 11, 2016, 11:54 PM | #57 |
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We're sure chasing this one down a rabbit hole! The physics discussion is being taken to a whole new level. The OP needs to forget physics and start studying the science of projectiles in flight called "ballistics". Physics alone can't answer his questions.
I love the "weaponizing math" kraigwy! I might have to steal that one in the future. My best advice is keep it simple, pick a caliber that has a large selection of projectiles with a decent BC. Make sure the rifle you choose has an adequate twist rate to stabilize the bullets you want to use. Find a cartridge with enough capacity to push your bullets 2700-3100 FPS at the muzzle and I can guarantee everything else will fall in place.
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June 12, 2016, 12:38 AM | #58 |
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I don't think the air will have any measurable effect on rocks being dropped for the first few seconds of falling. Dropped from 30,000 feet, I'm sure it would get to a velocity that the air resistance would have a large effect and the rock would probably reach a stable velocity if it's round, perhaps even slow down as the air gets denser. But a bullet fired level over a level plain from the altitude of the shooter's shoulder standing-off-hand will hit the ground at the same instant as a pebble dropped at the same exact time and altitude above the ground. I could be technically wrong, but that would be quibbling over nothing. The air resists the bullet's forward travel because its velocity is thousands of feet per second. But the air will not resist the bullet's vertical fall from your shoulder to the ground. Sometimes I think the quest to be technically correct can lead us to be practically wrong.
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June 12, 2016, 12:43 AM | #59 | ||
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In .1/2 seconds of freefall an object will be traveling ~4.9 m/sec or ~16.1 fps. Again, this can be tested with a big rock and a little rock in your back yard. Bullets in flight work the same way. The horizontal velocity of the bullet has no effect on the acceleration of gravity toward the ground. See the Mythbusters video above. Now if there was a minute or so of freefall, I suppose what you describe could happen, as the objects near terminal velocity, but that simply does not happen with rifle bullets. Quote:
Again, at the vertical velocities of a rifle bullet in flight, this is trivial at worst. Not sure if it is any consolation, but Aristotle agreed with you around 330 BC, but Galileo proved him wrong around 1600 AD. You are making this way more complicated than it actually is. |
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June 12, 2016, 05:34 AM | #60 | |
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June 12, 2016, 07:51 AM | #61 | ||
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"Shooting a handgun well is skill, shooting a rifle well is a science, and shooting a shotgun well is an art". |
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June 13, 2016, 09:34 AM | #62 | |
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Well said.
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June 13, 2016, 12:02 PM | #63 | |
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I always fancied myself a scientist. |
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June 13, 2016, 01:15 PM | #64 | |
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July 8, 2016, 07:28 PM | #65 |
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So anyway Im wondering what is the deal with Remington. As I said earlier in this thread I heard at a gun shop that Remington isn't what its used to be and that as of recently they have been producing junk. The salesman at the shop said that for considerably less money you could get a Savage Arms and you would end up with a significantly better gun. You would get more for less when you buy a Savage Arms instead of a modern Remington. Now its just plain common sense not to believe everything you hear at a gun shop or for that matter any shop. Shops are out to sell stuff and that being the case they will tell you whatever they need to in order to get you to buy. Not to buy good quality stuff but just to buy and to get money out of your pocket and into theirs. That is why Im taking it with a grain of salt about what I was told at the gun shop. And as far as the shop making money, the guy at the shop was pointing me in the direction of buying a Savage Arms gun which costs less than a Remington and the shop sold both. So that's another factor to consider, I was being advised to spend less money at the store not more if I wanted something better. Anyway, as I said I am well aware not to believe everything I hear at shops so that's why Im asking about it here. Is Remington having problems with their products as of recently? If I were to automatically believe what I was told at the shop I wouldn't be posting about it here, Im posting it here because Im researching if I should believe what I was told, that Remington now makes junk and that Savage Arms makes better products for a lower price.
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August 9, 2016, 12:22 AM | #66 |
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Anybody here?
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August 9, 2016, 02:55 AM | #67 |
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I thought this was already hashed out. Reread post #22 and make a decision; enough said.
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August 9, 2016, 10:06 AM | #68 |
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Remington quality has dropped off, but mostly fit and finish things, primarily driven by cost cutting. Savage fit and finish was never all that great to begin with, so it hasn't really changed.
This mostly applies to entry level rifles (SPS, ADL), the higher end Remingtons (BDL) still seem to be pretty good. If you build anything to a price point, you need to let some things slide, in this case the more labor intensive fit and finish. There is also the issue of the Walker trigger, a subject that has been truly beaten to death on this forum. Really doesn't matter at this point, you can no longer buy a new Remington 700 with the excellent Walker trigger. Modern manufacturing is excellent, even a cheap entry level rifle will outshoot most people. And a shop owner pointing you toward a lower priced item is really meaningless from the standpoint of how much money he will make, since you don't know how much they cost him. The lower priced item may have a higher margin. |
August 9, 2016, 10:06 AM | #69 |
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Well I want to make the point that if I hear something that doesn't necessarily mean I believe it. I want to verify if what I hear is true and so that's why I post it here and mention what I heard.
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