Information AboutRimfire |
| CATEGORIES ABOUT RIMFIRE AMMUNITION | |
| ammunition | |
| firearm terminology | |
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CHARACTERISTICS Rimfire cartridges, due to the thin case they must have, are limited to low pressure calibers. While in the past, rimfire calibers up to .44 (11 mm) were common, modern rimfires tend to be of caliber .22 (5.5 mm) or smaller. The low pressures mean that rimfire firearms can be very light and inexpensive, which has helped lead to the continuing popularity of the small caliber rimfire cartridges. ECONOMICS Rimfire cartridges are typically inexpensive, due primarily to large production quantities. A box of fifty inexpensive .22 Long Rifle cartridges typically costs less than US$1.00. Premium or match-grade .22 Long Rifle cartridges, as well as less common or out-of-production rimfire cartridges (such as the .22 Short , .22 Long , .32 Rimfire, .22 Winchester Auto, .22 WMR , and 5 mm Remington) can cost substantially more. HISTORY The first rimfire cartridge was the .22 BB Cap, which used no gunpowder by relying entirely on the priming compound for propulsion. Dating back to 1857 , the .22 BB Cap is essentially just a percussion cap with a round ball pressed in the front, and a rim to hold it securely in the chamber. Velocities are very low, comparable to an Airgun , as the round was intended for use in indoor shooting galleries. The next rimfire cartridge was the .22 Short, developed for Smith And Wesson 's first revolver; it used a longer rimfire case and 4 grains (260 mg) of Black Powder to fire a conical bullet. This led to the .22 Long, with a longer case and 5 grains (320 mg) of black powder. The .22 Long Rifle is a .22 Long case loaded with a longer, heavier bullet intended for better performance in the long barrel of a Rifle . The .22 Long Rifle is the most common cartridge in the world. While larger rimfire calibers were made, such as the .44 Henry and the .41 Remington, the larger calibers were quickly replaced by centerfire versions, and today the .22 caliber rimfires are all that survive of the early rimfires. The early 21st Century has seen a revival in interest in rimfire cartridges, with two new rimfires introduced, both in .17 caliber (4.5 mm). Below is a list of the most common current production rimfire ammunition:
A new and increasingly popular rimfire, the 17 HMR is basically a .22 WMR with a smaller formed neck which accepts a .17 bullet. The advantages of the 17 HMR over .22 WMR and other rimfires are its much flatter trajectory and its highly Frangible hollow point bullets (often with plastic "ballistic tips" that improve the External Ballistics performance). The key disadvantage of the .17 HMR is its cost (at present, over twice that of the .22 WMR). The even newer .22 Long Rifle based .17 Hornaday Mach 2 and offers similar performance advantages over its parent cartridge, also at a higher cost. While .17 HM2 sells for about US$6.00 per box of 50 rounds, six times the cost of inexpensive .22 Long Rifle ammunition, it is still significantly cheaper than most Centerfire ammunition, and somewhat cheaper than the .17 HMR. A notable rimfire still in production in Europe is the 9 Mm Flobert , which can fire a small ball, or even a small amount of shot like a small shotgun shell. The 9 mm flobert is often called a "garden gun" in the UK, as its power and range are minimal, and it is well-suited for use in gardens, where the next-largest shotgun (a .410 Bore ) would be too devastating amongst the cabbages. The 9 mm Flobert is used to eradicate vermin such as mice and rats, and pigeons roosting in sheds. SHOT There is a type of ammunition for the .22LR that fires a small amount of #12 shot. The shot is only marginally effective in close ranges, and is usually used for shooting rats or other small animals. This cartrige is becoming rare, as it can ruin the barrel of the rifle if the barrel is not properly cleaned after shooting of this ammmunition. (unless it is a specially-made smoothbore .22), doesn't feed well in many semi-auto rifles, and has a very short effective range (less than 10 metres). |
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