G W Wade Posted November 4, 2014 Share Posted November 4, 2014 cabin fever struck me 2 yrs ago and I ended up with a 458 socom. imagine 45/70 semi auto==300gr hp@2000fps and 405sp@ 1700fps. downside 30 rds mag only holds 9 but heck I never needed more than 1 yet. Regards GW Link to comment Share on other sites More sharing options...
Elk Creek LeMieux Posted November 4, 2014 Share Posted November 4, 2014 As far as barrel length goes, don't let anyone tell you that 16" will shoot as well as 20". I started out with a 20" barreled M-16, before the shorter M-4 type rifles. I could tell a difference as soon as I put them on paper. Went from easy dime size groups with the 20 inch barrel to nickle size with the shorter M-4 type barrels. 10" barrel nets somewhere between a nickle and a quarter for me. That's all 1:7 rifling, and military "surplus" ammo. Now, I'm not a great shot... But I shoot well enough to see consistent groups with each barrel length. And as the barrel gets shorter, the groups get bigger. Not so big that you couldn't hit a man sized target at 300 meters, but not small enough to net head shots on those zombies at that distance. Link to comment Share on other sites More sharing options...
John E. Law Posted November 4, 2014 Share Posted November 4, 2014 I know he already has his gun picked out but if you really want long range with an AR there is now this. http://nemoarms.com/portfolio/omen-match-300-win-mag-ar/gallery/guns/#!prettyPhoto JEL Link to comment Share on other sites More sharing options...
Muleshoe Bill SASS #67022 Posted November 4, 2014 Share Posted November 4, 2014 Forearm??? We dont need no stinken forearm Link to comment Share on other sites More sharing options...
Muleshoe Bill SASS #67022 Posted November 4, 2014 Share Posted November 4, 2014 Link to comment Share on other sites More sharing options...
Elk Creek LeMieux Posted November 4, 2014 Share Posted November 4, 2014 That diagram is a good example of how much difference different loads can make. A 150 grain bullet out of that .308 at around 2800 feet per second has no where near that much drop at 500. Memory fades, but the rifle I hunted with in high school was good to 400 without much hold-over. That's as far as I ever shot it, and that was playing around with a target, not an animal. I can't imagine that 150 grain load loosing that much between 400 and 500 though. Link to comment Share on other sites More sharing options...
Echeconnee Drifter Posted November 4, 2014 Share Posted November 4, 2014 That diagram is a good example of how much difference different loads can make. A 150 grain bullet out of that .308 at around 2800 feet per second has no where near that much drop at 500. Memory fades, but the rifle I hunted with in high school was good to 400 without much hold-over. That's as far as I ever shot it, and that was playing around with a target, not an animal. I can't imagine that 150 grain load loosing that much between 400 and 500 though. A 150 grain load out of the .308 should have at least that much drop or more, depending on the specific bullet design and the initial muzzle velocity. That heavy bullet was chosen because it's one of the best .308 designs for long range. The Sierra Match King is really top notch, only surpassed by even more expensive designs from places like Berger. Beyond 300 yards, initial velocity matters far far less than bullet shape. Atmospheric drag slows the bullet at an exponential rate related to its speed - the faster the bullet, the faster the air compression and friction slows it down. That means your best bet for reducing drop at long range is to fire a bullet design like that 175 Grain Hollow Point Boat Tail Sierra Match King. Let's run some numbers from some common .308 target ammunition - Federal American Eagle. This has an advertised muzzle velocity of 2,820 feet per second. The bullet has a ballistic coefficient of 0.408. According to the Shooter's Calculator, the bullet drop between 400 and 500 yards is a difference of 26 inches which pretty much exactly matches what you see from the heavier bullet above. At ranges beyond 500 yards, the difference is only going to become more dramatic. Link to comment Share on other sites More sharing options...
Seldom Seen #16162 Posted November 4, 2014 Share Posted November 4, 2014 Lumpy, the Kid's impressed with the reported accuracy, ballistics, and residual velocity and energy past 800 yards. Now, as kindly as I can say this, he's researched and discussed it at length, and decided this is what he wants. And as a "fun gun," not a "SHTF gun." He has other options for that. I predict you will continue to get advice on calibers (which he already decided on), and rifles (which he already bought). Any of the big names in ARs would be a fine choice for the upper. He just needs to decide on bbl length, sights and forearm. He needs to get a Glock. Lord forgive me I just couldn't help myself. I got caught up in it being election day. Link to comment Share on other sites More sharing options...
Utah Bob #35998 Posted November 4, 2014 Share Posted November 4, 2014 That diagram is similar to the trajectory of this thread. Link to comment Share on other sites More sharing options...
Elk Creek LeMieux Posted November 4, 2014 Share Posted November 4, 2014 A 150 grain load out of the .308 should have at least that much drop or more, depending on the specific bullet design and the initial muzzle velocity. That heavy bullet was chosen because it's one of the best .308 designs for long range. The Sierra Match King is really top notch, only surpassed by even more expensive designs from places like Berger. Beyond 300 yards, initial velocity matters far far less than bullet shape. Atmospheric drag slows the bullet at an exponential rate related to its speed - the faster the bullet, the faster the air compression and friction slows it down. That means your best bet for reducing drop at long range is to fire a bullet design like that 175 Grain Hollow Point Boat Tail Sierra Match King. Let's run some numbers from some common .308 target ammunition - Federal American Eagle. This has an advertised muzzle velocity of 2,820 feet per second. The bullet has a ballistic coefficient of 0.408. According to the Shooter's Calculator, the bullet drop between 400 and 500 yards is a difference of 26 inches which pretty much exactly matches what you see from the heavier bullet above. At ranges beyond 500 yards, the difference is only going to become more dramatic. I will submit to your knowledge on the subject. I didn't hold 2 feet over the target at 400 yards though, must be what got me twisted on the subject. Link to comment Share on other sites More sharing options...
Hardpan Curmudgeon SASS #8967 Posted November 4, 2014 Author Share Posted November 4, 2014 He needs to get a Glock. Lord forgive me I just couldn't help myself. I got caught up in it being election day. Maybe. I do know he's having "buyer's remorse" over his S&W Shield... doesn't like the trigger (his finger doesn't naturally fall on the "business" part of it), the so-called safety is a PITA (very low-profile), but the worst is the slide. Dang wavy "serrations" are so shallow and smooth it's like trying to pull a bullet out of a case with your fingers. Purty, but useless. Some engineer needs to go re-take the "function over form" class! Link to comment Share on other sites More sharing options...
John E. Law Posted November 4, 2014 Share Posted November 4, 2014 That diagram is similar to the trajectory of this thread. Well since its way off track I'll ask Drifter this. Disclaimer: I am a shooter and not (by far) a ballistics expert. I learn what works from friends then I go from there so this is just a just a question. I've always been told and under the impression that BC is THE main factor in long range ballistics. I have 2 identical rifles 1 in 7.62x51 the 2nd in 7mm Rem Mag. With identical Leupold MK 4 scopes. The bullets are both Sierra MK one is 168gr (.30) the other 165gr. (7mm). The 168gr is at 2850fps the 165gr is at 1925fps. The ballistic coefficients are .4 Link to comment Share on other sites More sharing options...
John E. Law Posted November 4, 2014 Share Posted November 4, 2014 I phone glitch. Continued .468 (.30) and .550 (7mm) At 600yds the 7.62 is at 72.4 in elevation and the 7mm is only at 63.7 in. At 1000yds the 7.62 is at 268in and the 7mm is only at 230in. So if they're traveling roughly the same velocity the BC of the 7mm......, Um never mind I just reread you post and found that I read it wrong......my bad ignore post 😃 JEL Link to comment Share on other sites More sharing options...
Badger Mountain Charlie SASS #43172 Posted November 4, 2014 Share Posted November 4, 2014 Just a question here from a nimrod. Was the AR platform ever intended to be used as a "sniper" or "long range" type weapon? I have always heard that it was intended to pin down the bad guys until the heavy stuff could snuff them out. I realize that the Nato 5.56 round will travel some distance with accuracy, but I question it's knockdown at 600 yards+. Apparently the military agrees with me, because they use a .30 caliber round or greater for sniper operations. Of course this come from a guy that shot a 81mm firearm. Link to comment Share on other sites More sharing options...
Elk Creek LeMieux Posted November 4, 2014 Share Posted November 4, 2014 Just a question here from a nimrod. Was the AR platform ever intended to be used as a "sniper" or "long range" type weapon? I have always heard that it was intended to pin down the bad guys until the heavy stuff could snuff them out. I realize that the Nato 5.56 round will travel some distance with accuracy, but I question it's knockdown at 600 yards+. Apparently the military agrees with me, because they use a .30 caliber round or greater for sniper operations. Of course this come from a guy that shot a 81mm firearm. No I don't believe it was. That said, I can't think of many rifles the military has used that haven't proven to be quite accurate. The 5.56 is versitile enough to find it's way into a few designated marksman rifles though. AKA, M-16's with long(er) range scopes. Link to comment Share on other sites More sharing options...
Echeconnee Drifter Posted November 4, 2014 Share Posted November 4, 2014 Um never mind I just reread you post and found that I read it wrong......my bad ignore post Haha! We all have those days! For the record, I'm not a ballistics expert either and don't do any long range shooting, I just understand the physics involved pretty well. The ballistic coefficient is a huge part of long range shooting, but initial velocity and such factors in as well. Basically, the ballistic coefficient only tells you how well the bullet is at overcoming drag (air resistance if you will). That in and of itself tells you very little if anything about things like drop or drift from cross winds or other factors. Muzzle velocity is another big part of it. Image for a moment that some one made some super-duper bullet with a ballistic coefficient of let's say 15.0. That's ridiculous I know, but let's assume that's the case. If it's fired from a Colt Clone at a muzzle velocity of only six hundred feet per second, it's still going to hit the ground at a much shorter distance than either of your SMKs in the 7.62x51 or 7mm Remington Magnum. Basically, the longer a bullet is in the air, the more time that gravity has to pull it down to the ground. The ballistic coefficient has very litte to do with the effect of gravity. That is only overcome by the angle of the shot and the velocity of the bullet as it flies through the air. A high ballistic coefficient will allow it to stay in the air longer (if fired at the same angle and initial velocity) because drag slows it down less. But both bullets will be in the air the same exact amount of time. I'll stop before I start making things even more complicated. Suffice it to say that at ranges beyond say 400 or 500 yards, the 6.5 Grendel is superior to the .308 Winchester in pretty much every way. At ranges shorter than that, the .308 is the better choice performance-wise. Link to comment Share on other sites More sharing options...
Echeconnee Drifter Posted November 4, 2014 Share Posted November 4, 2014 A high ballistic coefficient will allow it to stay in the air longer (if fired at the same angle and initial velocity) because drag slows it down less. But both bullets will be in the air the same exact amount of time. I should clarify here. The problem is that I'm confusing the word "longer". At one point I use it to mean "a longer period of time" and in another place I use it to mean "a longer distance". Here's what I should have said: A high ballistic coefficient will allow the bullet to travel a longer distance in the same amount of time (if fired at the same angle and initial velocity) because drag slows it does less. But both bullets will be in the air the same exact amount of time (again given they were fired at the same angle and initial velocity). Link to comment Share on other sites More sharing options...
Hardpan Curmudgeon SASS #8967 Posted November 4, 2014 Author Share Posted November 4, 2014 And Galileo couldn't have explained it any more clearly at the Tower of Pisa. Galileo Link to comment Share on other sites More sharing options...
Echeconnee Drifter Posted November 4, 2014 Share Posted November 4, 2014 And Galileo couldn't have explained it any more clearly at the Tower of Pisa. Galileo Nice little demonstration widget there. I'm not sure the account of Gallileo at the Leaning Tower ever actually happened though. The way Gallileo proved this, at least to himself, was by rolling dissimilar balls down slight inclines. By doing this, he increased the amount of time it took for the balls to reach the ground and let him observe things more clearly. He discovered that the weight of the balls didn't matter. Balls of vastly dissimilar weights rolled off the ends of the ramp at precisely the same time. He also devised an experiment for measuring the speed of light, but couldn't get solid data. In the end he determined that light was either infinitely fast, or some ridiculously fast that he couldn't figure out a way of measuring it. Gallileo was a ridiculously intelligent man and doesn't get the sort of notoriety he deserves. In many ways he pioneered most of Newton's latter accomplishments. Link to comment Share on other sites More sharing options...
Utah Bob #35998 Posted November 5, 2014 Share Posted November 5, 2014 I thought Galileo dropped an apple on Newtons's head from the tower of Pisa.n That's what I get for depending on Prof. Peabody for my history. Link to comment Share on other sites More sharing options...
Badger Mountain Charlie SASS #43172 Posted November 5, 2014 Share Posted November 5, 2014 He77. I thunk it was the leaning tower of Pizza and Lugie and Guido had a Pizzeria inside. So much for my social graces. Link to comment Share on other sites More sharing options...
Gunner Gatlin, SASS 10274L Posted November 5, 2014 Share Posted November 5, 2014 He77. I thunk it was the leaning tower of Pizza and Lugie and Guido had a Pizzeria inside. So much for my social graces. Hock a Lugie?? GG Link to comment Share on other sites More sharing options...
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