http://www.huntingnut.com/ HuntingNut en-us Mon, 26 Dec 2011 04:09:43 GMT 1440 CPG-Nuke Dragonfly HuntingNut News http://cyber.law.harvard.edu/rss/rss.html http://www.huntingnut.com/images/logo.gif http://www.huntingnut.com/ http://www.huntingnut.com/index.php?name=News&file=article&sid=81 [size=14]I decided I needed to build a bullet trap to test terminal performance as part of my decision making process for hunting bullet selection. I was trying to decide which new .223 bullets might be a capable hunting bullet for small deer, the Barnes 62gr TTSX or the Hornady 70gr GMX (Hunting with the .223). I first studied how to make blocks of ballistic gelatin, the industry standard for testing bullet terminal performance. Ballistic gelatin is a testing medium that scientifically correlates to swine muscle tissue. However, the process of making the gelatin and using it is complicated. Water has to be heated to make the gelatin and then the mixture has to be refrigerated. The gelatin is also supposed to be at a specific temperature for valid test results, 39F or 50F depending on its composition. I needed something a bit easier to work with and one that didn Mon, 26 Dec 2011 04:09:43 GMT http://www.huntingnut.com/index.php?name=News&file=article&sid=80 There is always a great deal of chatter among hunters, as well as shooters primarily interested in defense, about "energy" and "momentum" and how they relate to "knock down power", etc. I find, however, that the terms used are often misunderstood. Having been involved in so many of these discussions I thought I'd offer some definitions and examples of what these terms mean with regard to terminal ballistics, that is, what happens when a bullet hits a critter or other target. Before I even get started I want to recommend an excellent book every serious shooter ought to have. "Understanding Firearm Ballistics" by Robert A. Rinker should be required reading for anyone who wants to really know how internal, external and terminal ballistics works. The book offers relatively simple explanations of the nuts and bolts of ballistics and also includes the formulas to go deeper into it if you want to. I don't know of any better reference for those of us who want to really understand ballistics. The first thing we need to do is define a few of the terms that get used so often. I'll have a list of my references at the end of this article. Forgive me for using "English" units instead of metric units but I'm just used to them! Mass - Mass is the amount of matter that makes up an object. The unit used for this is the "slug". It isn't the same thing as weight. If an object is in space it has almost no weight but still has the same mass as on earth. An object's mass can be calculated by dividing its weight in pounds by the acceleration due to gravity, which is 32.12 ft/sec/sec. Since we used "grains" to measure bullet weight we also have to convert grains to pounds before dividing by gravity. There are 7000 grains in a pound. For example: a 150 grain bullet would weigh 150/7000 = 0.02143 pounds. Its mass would be 0.2143/32.12 = 0.000667 slugs. Velocity - Velocity is simply how fast our object is going. In shooting we usually measure velocity in feet per second (ft/sec). Momentum - This is the "push" you get from a bullet leaving the gun and also hitting its target. Momentum is calculated by multiplying an object's mass by its velocity. When people are talking about an "equal and opposite reaction" in shooting this is what they mean. The bullet and propellant gases go one way and the rifle goes the other way. The unit used is the slug-foot/sec. A 150 grain bullet going 2900 ft/sec has a momentum of 1.935 slug-ft/sec. Energy - Energy is the ability to do work. In shooting we are talking about "kinetic energy", that is, the energy of a moving object. The unit we use for energy is the "foot-pound". To calculate an object's kinetic energy you have to know its mass and its velocity. The formula for kinetic energy: KE = 1/2 x mass x velocity x velocity. A commonly used method to calculate energy of a bullet is; bullet weight x velocity x velocity / 450380. The constant of 450380 takes care of the conversion from grains to slugs. Our 150 grain bullet going 2900 ft/sec has an energy of 2801 foot-pounds. So, what's all this stuff mean to us shooters? Let's look at what momentum and energy actually do for us, and to the targets. Keep in mind that there are a lot of variables that will muddy the water here. As mentioned above, momentum is the "push" the moving bullet gives to both the rifle and the target. When the bullet leaves the muzzle the "equal and opposite reaction" is pushing the gun back against us. That's recoil. When we calculate recoil we also have to take into account the weight and velocity of the powder gases. The velocity of the gas is usually estimated as 1.5 times the velocity of the bullet. If we take that 150 grain bullet at 2900 ft/sec, along with a 50 grain powder charge exiting the muzzle at around 4350 ft/sec, and fire it in an 8 pound rifle we'll have the rifle coming back at us at about 12 ft/sec. But, if we are holding the rifle correctly, you also have to include our mass in the calculation. A 180 pound man firing that rifle would be given a backward velocity of about 0.5 ft/sec. Now for some of those variables. Our muscles aren't rock hard (as much as we'd like to believe they are!) so they soak up part of that recoil. So do any recoils pads. The stock material and design can make a difference too. The point to take away here is that the recoil isn't going to knock us into the next county, even if it does smart some. Now, how does the momentum affect the target? In every single case the bullet will hit the target with less momentum than the gun hits the shooter. Remember that part of the gun's recoil comes from the propellant gases and those don't make it to the target. If you're shooting a steel plate like a metallic silhouette ram, which weighs around 50 pounds, you can give the plate a velocity of 1.24 ft/sec. That's enough momentum to tip it over, if the base isn't too wide. Since the bullet doesn't go through the plate it transfers all of its momentum to the plate. You might even get a little extra push if the bullet spatters back toward the shooter. If you are shooting a 150 pound deer (or bad guy), and the bullet doesn't go all the way through, you'll again transfer all of the momentum to the target. In this case the velocity you'll give the deer is a little over 0.4 ft/sec. If the bullet passes through the target the momentum would be even less. We've all heard stories of deer being knocked down, flipped over, etc. when struck by a bullet but those incidents are the result of the reaction the animal made to being struck, not the momentum itself. It's like a person reacting to a bee sting. The momentum of the sting doesn't cause all those contortions and gymnastics, the person's reaction to the sting does. The big variable here is whether the bullet stays in the critter or passes all the way through. The take away, however, is that there really isn't any such thing as "knock down power" except maybe on very small critters. How about this energy thing? As mentioned above, energy is the ability to do work. In the case of a moving bullet the energy gets used up on several ways. Initially some of the available energy is used up by pushing through the air on the way to the target. More is used creating heat and noise. On impact energy is used by making a hole in the target and deforming the bullet. The big variables to remember here are the bullet's construction and the target's construction. When you start comparing loads using their energy levels you need to make sure that you're comparing apples to apples. Let me offer a couple of examples to illustrate my point. If I take identical 150 grain .30 caliber spire point bullets and load one in a .30-30 and the other in a .30-06 I'm going to get somewhat different results when the bullet hits the target. The .30-30 will start the bullet off at around 2200 ft/sec and at 100 yards will have an energy of 1300 foot-pounds. The .30-06 will start the same bullet at 2900 ft/sec and at 100 yards will have an energy of 2317 foot-pounds. With that extra energy the .30-06 will do more tissue damage and also deform the bullet more. What if we took two bullets of the same weight but very different construction and loaded them so that they would strike the target with exactly the same energy? Let's say that I load a very frangible bullet, like a Barnes "Varmint Grenade" in one case and a monolithic bullet, like a Barnes TSX, in another. In this case the frangible bullet would come apart on impact, creating a shallow wound. The monolithic bullet would stay together and keep penetrating the target. If we're talking about a small critter this doesn't make much difference but if we are talking about a deer-sized critter it could easily mean the difference between a lost animal and venison steaks on the grill. The point to all this is that neither momentum nor energy are magic numbers. Momentum won't knock big game over and energy alone won't cause humane kills. When you start making comparisons of cartridges you also must keep in mind the bullet construction. Also keep in mind that there are a number of other variables that will affect the terminal performance of the loads. The biggest variable of all while hunting (and defensive shooting) is shot placement, and that takes practice with the gun, not the calculator. References: "Understanding Firearm Ballistics" by Robert A Rinker "Applied Physics" by Paul E. Tippens "Principles of Physics" by Frederick Bueche Fri, 16 Sep 2011 21:08:43 GMT http://www.huntingnut.com/index.php?name=News&file=article&sid=79 PRIMERS AND PRESSURE by James Calhoon (First Printed in Varmint Hunter Magazine, October, 1995) In the course of talking to many shooters, it has become clear to me that the manufacturers of primers have done a less than adequate job of educating reloaders on the application of their primers. Everybody seems to realize that some primers are "hotter" than others and some seem to shoot better for them than others, but few reloaders know that primers have different pressure tolerances. I ran into this problem myself when loading a 223 to the maximum. The primer I was using was piercing before the case began expanding at the head or reaching maximum pressure. How do you check maximum pressure without a laboratory pressure gun, you ask? To check maximum pressure on a given powder / bullet combination, measure the rim of the cartridge (at a specific point each time of the measurement) before and after firing. Cases don Sun, 06 Mar 2011 18:53:46 GMT http://www.huntingnut.com/index.php?name=News&file=article&sid=78 [size=14] My scout master presented me with a .43 Egyptian Remington Rolling Block back in Fri, 02 Apr 2010 17:10:14 GMT http://www.huntingnut.com/index.php?name=News&file=article&sid=77 by Mike Hines I seem to see the same kind of question over and over again in the online forums that are about reloading your own ammunition. Fri, 26 Mar 2010 18:48:57 GMT http://www.huntingnut.com/index.php?name=News&file=article&sid=76 Two that got way, one due to their diligence one due to nerves. We were hunting caribou in Alaska southwest of Bethel. The river road was very bust that morning with shoppers and hunters all traveling before the sun was above the horizon. Because of our geographic position on the planet the sun comes up more in the north than the east. Traveling down river heading south the sun came up over my right shoulder. About 40 miles outside of town we saw one caribou about 1000 yards out. Caribou usually travel in groups. Not wanting to drop the dime as it were we waited until the other hunters kept moving. ( knowing there had to be other caribou there ) We waited and waited but only one caribou was to be seen. Planning our stalk the wind was in our favor. We traveled about a mile ahead and layed in wait for the "unsuspecting" prey to walk in to my sights. Plan A did not work. Plan B was to approach using the frozen sloughs, and staying out of sight. It was during this phase we notices all the wolf tracks. A lone caribou on the tundra with all there wolf tracks he had to be one very cautious critter. Either by sent or motion the jig was up. Time for plan C. Get back to the snow-go travel to the east a long way and loop around behind him. 10 miles and we started to head back north. Just off a big lake we stop to glass for caribou and see something small coming across the ice behind us. I'm thinking what is following us. Way to small to be a bear? Forgetting all about the caribou we watch and wait. The lopping gait is not familiar it doesn't move left or right just straight ahead coming toward us. The wind is out of the east, and beasty is coming from the south. At what must be 100 yards we recognize what it is a real live wolverine. Following us ! I didn't want to shoot it. I suppose I could have I just didn't want to. So it comes closer. Finally we let it know where we were by moving. Nothing, no reaction what so ever! The wolverine changed direction somewhat but gave no indication it cared or was concerned we were there. After passing us we watched with amazement as it went into a willow thicket. Being curious we followed up until the snow got to knee level. Wolverine tracks were everywhere. Mr. or Mrs. wolverine had themselves a den in that mess. So there it was in one day, two critters no shooting. One so scared it was darn near paranoid, the other so darn confident it lead us to it's home. The yupiks said the wolverine was following us looking for a gut pile. Knowing we were "gusicks" it had no fear of us. It got me to thinking who was hunting who? Longwalker Wed, 24 Feb 2010 18:29:30 GMT http://www.huntingnut.com/index.php?name=News&file=article&sid=75 [size=14] If this buck was 420 yards away, could you take this shot with confidence? This article describes how a hunter can use a duplex reticle and a variable power scope to compensate for bullet trajectory at longer ranges, or commonly referred to as bullet drop compensation (BDC). I was motivated to start this project when I began looking for a scope that provided BDC capability to mount on my newly acquired .270 Winchester. I looked at scopes from Burris, Cabella Wed, 09 Sep 2009 15:42:59 GMT http://www.huntingnut.com/index.php?name=News&file=article&sid=74 [size=14] If this buck was 420 yards away, could you take this shot with confidence? This article describes how a hunter can use a duplex reticle and a variable power scope to compensate for bullet trajectory at longer ranges, or commonly referred to as bullet drop compensation (BDC). I was motivated to start this project when I began looking for a scope that provided BDC capability to mount on my newly acquired .270 Winchester. I looked at scopes from Burris, Cabella Wed, 09 Sep 2009 15:41:05 GMT http://www.huntingnut.com/index.php?name=News&file=article&sid=73 [size=14] In the process of researching a new scope selection, I investigated the bullet drop compensation (BDC) reticles I found in scopes that I could afford to purchase. I saw no clear choice for my application. Each manufacturer Thu, 03 Sep 2009 18:53:07 GMT http://www.huntingnut.com/index.php?name=News&file=article&sid=72 Ruger #1 Accuracy by Ed Harmon First a notification: Ruger takes the position that any modification to their guns voids their warranty. They also consider hand loads a no-no. If you return a gun for work that has been modified they may just return it without work being performed and charge you shipping, so be aware and consider the potential consequences before you modify your Ruger firearm. Forearm The #1 and the #3 Rifles, upon examination, are obviously designed to have the forearm separated from the barrel otherwise the forearm would be screwed to the barrel, like a Martini or Martini Cadet. The two actions are the same without the levers and both will take the same barrels. Why are the barrels not free floated from contact with the wood of the forearm at the factory? Forget the hype, it is purely economic. To get the correct clearance under the barrel and along each side of the barrel, takes time and time is money in manufacturing. Ok, we start by removing the forearm from the rifle. You can, if you wish, try the O ring trick by buying a couple of O rings at the hardware store to fit the shank of the forend screw. Before any modification, put one O ring at a time between the hangar and the wood. This sometimes will work. Otherwise we continue. If you are familiar with glass bedding a rifle to start with, you relieve the wood to provide an even line down both sides of the barrel; a barrel channel rasp helps to make this job quick and easy. If you have not done a glass bed for a barrel channel before, put the forearm back in place, run a pencil down the wood, alongside the barrel and cut the wood back to the pencil line using a barrel channel rasp. Go slow; it is difficult to stick wood back on. Use a fine cut flat wood rasp or a course flat steel file to straighten the lines if needed. Then use a sanding block to finish. You will need one layer of Duct Tape on each side for clearance. Stick a layer of duct tape on the barrel lengthwise and when the forearm fits back on the barrel just a bit snugly, you are about right. Once you get the sides cut you can start on the bottom, where the hanger makes contact. With an oil burner, soot up the hangar and barrel, pressing the forearm into place. With the barrel channel rasp remove all marks in the barrel channel. Then go back to the hanger contact area and with a motor tool and small carbide router bit, remove the marks or the contact points made by the hanger. You only need to rough up three points because the will need to be extended or built up in any case. In the attached photos an arrow points to the three places that require glass. All you need do is rough the surface of the wood so the glass will stick, without peeling or flaking off. Put two layers of duct tape only along the bottom of the barrel then coat the metal and the tape with Johnson Thu, 27 Aug 2009 17:45:38 GMT