Here is my take on AK (Kalashnikov) style rifles vs AR-15 style rifles. For simplicity's sake, I will consider AKs in 7.62x39 and ARs in 5.56x45 NATO. I own both, and I like both, and I have experience running both in carbine classes, for whatever that's worth. AKs and ARs have different design decisions. In general, the design decisions that give one its strength, also give it its weaknesses.
That said, ARs are more reliable than people think and AKs are more accurate than people think, and it's really just a matter of preference.
AR advantages:
- Lighter, in part due to having an aluminum receiver and no piston and a lighter, hollow bolt carrier.
- Lighter and smaller magazines and ammo. Since the magazines are more or less rectangular, they are easier to stack and fit into boxes or dump pouches compared to the curved AK mags.
- More accurate, in part due to tighter tolerances and lack of a heavy bolt carrier and piston slamming around.
- More ergonomic controls, especially the safety which can be manipulated very quickly with the thumb, and the charging handle which can be run with the left hand easily. The AK has the charging handle on the right side of the gun, which makes it a little awkward to run with the left hand, and it has the safety forward on the right side of the gun, which requires breaking the firing grip at least somewhat to manipulate it.
- The bolt locks back when the mag is empty, which lets you know when you're empty and enhances the speed of emergency reloads. AKs do not have this feature, and with an AK you usually know you're empty when you hear the click of dropping the hammer on an empty chamber.
- The bolt can be locked back manually. There's no way to lock back the bolt period on a stock AK, although aftermarket selectors with a cut out to allow locking the bolt back are available.
- The sight radius for iron sights is much longer, since the rear sight is at the rear of the receiver. On an AK, the rear sight is relatively far forward in the middle of the receiver, leading to a shorter sight radius. Also, an AR's aperture style rear sight is generally considered more accurate than the AK's notch and post sights.
- The process of reloading the AR is a little bit faster than that for reloading an AK.
AK advantages:
- More intrinsically reliable and low maintenance. Here are some factors that play into the AK's reliability:
- The bolt carrier and piston are heavy, and the system is 'overgassed', i.e. the amount of gas that is transmitted through the gas tube to the piston is significantly more than is strictly needed to cycle the bolt. These factors help the bolt smash through friction due to dirt or lack of lubrication, but also hinder accuracy.
- The stroke of the bolt is significantly longer than what would be needed to extract and eject the empty case and feed a new round from the magazine. So weak or erratic ammo is tolerated.
- The 7.62x39 and 5.45x39 cartridges are both tapered more than 5.56, so extraction is enhanced.
- There is a lot of room in the receiver. Dirt, blown primers, or cases that fail to eject have enough room to generally not get stuck and cause problems. Compare to the AR, where there is exactly enough space above the bolt for an empty case to get stuck, and exactly the amount of space in the gas key for a small rifle primer to get stuck.
- The extractor on an AK is large and beefy compared to that on an AR. The ejector on an AK is a fixed piece of metal integral to the receiver which is simple and robust. The ejector on an AR is an assembly of little parts in the bolt which includes a pin, the ejector, and a spring.
- The recoil spring is in the receiver, unlike the AR which has the recoil spring in the stock. So AKs can have folding stocks.
- An AR's bolt carrier has holes in it that can allow dirt and grit to get inside the bolt carrier if the dust cover is not closed. An AK has a solid bolt carrier with no dust cover needed.
- Some malfunctions on an AK are generally easier to clear. In a double feed, the magazine can be removed without needing to lock the bolt back, so the procedure to clear it is to simply remove the magazine, rack the bolt a few times, and reload. Clearing a 'brass over bolt' malfunction in an AK is made much easier by just removing the top cover and then picking out the piece of brass.
- The rock and lock magazine mechanism on an AK allows easily seating a full magazine when the bolt is forward. On an AR, many users load their mags to 28 or 29 rounds to ease seating the mag when the bolt is forward.
- Ammo is generally cheaper for the AK, especially if you can find military surplus ammo. AKs run well with cheap steel cased ammo, which can be hit or miss in an AR.
- An AK is less expensive than a comparable AR.
Tuesday, April 10, 2012
Friday, April 6, 2012
Tourniquets for emergency trauma to extremities
First, let me say that I am not a medical professional and am not qualified to give medical advice. I do have some very basic training in trauma medicine. I am posting this to get you thinking about this subject, but you really need to do your own research and ideally get some professional training. Tourniquets can be dangerous and should only be used by those with basic training in their use.
Why tourniquets?
It's best to have a well rounded medical kit for your range bag, and probably on your person while undergoing firearms training. But tourniquets have a special place in emergency trauma, and I would recommend having multiple tourniquets on your body while training.
Some advantages they have:
- They require relatively little training to use properly. Note: it is very important to at least have some training and a firm understanding of where to place the tourniquet given different locations of wounds.
- They can be applied very quickly to one's self even with only one hand(since you may have lost the use of the arm that got injured). Using bandages is relatively difficult and slow one handed, and may not stop the bleeding with large wounds. Also, bear in mind a gunshot wound usually has an entry wound and an exit wound. It would be very difficult to bandage both wounds properly and quickly, especially with one hand. With a tourniquet, it doesn't make much difference that there are two wounds.
The speed with which you stop the bleeding is very important. I couldn't find a reputable citation with a quick search but with femoral arterial bleeding it seems generally accepted that it's possible to bleed out in under 3 minutes, and to lose consciousness well earlier than that.
- They are effective in preventing blood loss in most extremity wounds (wounds to the arms or legs). Extremity wounds comprise the majority of traumatic injuries in US armed conflicts. See http://www.ncbi.nlm.nih.gov/pubmed/17414553
Extremity wounds are easier to self-treat than torso or head wounds.
- They are very light and compact (about the volume of two fingers, and weighing about two to five ounces)
- They are inexpensive. The CAT or SOFT-T can be had for about 25 to 35 dollars.
- You can train with them to some degree without using them up. You can practice putting a tourniquet on without worrying about wearing it out or getting it un-sterile. Obviously if you put a tourniquet on 100 times, that might start to wear it out, but a certain amount of training is fine. For fast access, you can easily connect it to the outside of your gear or rifle. See the "How to carry tourniquets" section below for more. Compare this to bandages; they must be kept in their sterile packaging so to take one out for training or leave one exposed outside of a pouch would ruin it.
But what about the risk of losing the limb?
The old school of thought was that tourniquets should be a last-ditch solution, and that use of a tourniquet would necessitate amputation of the limb. Recent military experience has shown that modern tourniquets can be in place for at least two hours with a very low risk of losing the limb as a result of the tourniquet. See the links at the end for references.
"A series of studies have looked at the efficacy of prehospital tourniquets and their safety.(16–18) The conclusions are overwhelmingly in favor of applying tourniquets to control severe extremity hemorrhage. In addition, they highlight the near-total absence of significant complications attributable solely to the use of tourniquets. ... Instances of effective tourniquets being placed for up to 20 hours have been recorded with complete viability of the limb and return to full duty."
Which tourniquets?
Specific tourniquets I recommend are the CAT or SOFT-T Wide.
Between the two, the CAT is lighter because it has a plastic windlass, but the windlass is less durable for the same reason. The SOFT-T has an aluminum windlass. I would take the SOFT-T unless you are very concerned about a few ounces of weight, or if you're going through a lot of metal detectors.
The SWAT tourniquet has its place, but consider that it will be difficult to apply one handed, and since it has no windlass, you can't fine tune the pressure that is applied. See also "Risks of Rubber Band Tourniquet Use"
If you're going to carry one tourniquet, you probably should consider carrying two. Your legs are very close together and if someone's taking multiple shots at your legs, if one leg is hit there is a pretty high likelihood that the other will be hit as well.
How to carry tourniquets:
- In a pocket.
- In a medical kit pouch
- On MOLLE: The Blue Force Gear Tourniquet Now! or the Mayflower tourniquet holder. Or you can rig your own using shock cord: http://jerkingthetrigger.com/blog//2010/03/12/tactical-handyman-tournequit-retention-doohicky/
Any closed-top single pistol mag pouch would probably work as well.
Thinking about making sure you can access the tourniquet with either hand in case the other arm is injured.
References:
http://www.cbsnews.com/8301-18563_162-57339769/how-a-simple-tool-saved-many-u.s-lives-in-iraq/
http://www.jems.com/article/patient-care/civilian-ems-should-consider-tourniquets
http://www.jems.com/article/major-incidents/tourniquet-first
http://www.jems.com/article/patient-care/return-tourniquets-original-re
http://www.ncbi.nlm.nih.gov/pubmed/12768129
http://journals.lww.com/annalsofsurgery/Abstract/2009/01000/Survival_With_Emergency_Tourniquet_Use_to_Stop.1.aspx
Why tourniquets?
It's best to have a well rounded medical kit for your range bag, and probably on your person while undergoing firearms training. But tourniquets have a special place in emergency trauma, and I would recommend having multiple tourniquets on your body while training.
Some advantages they have:
- They require relatively little training to use properly. Note: it is very important to at least have some training and a firm understanding of where to place the tourniquet given different locations of wounds.
- They can be applied very quickly to one's self even with only one hand(since you may have lost the use of the arm that got injured). Using bandages is relatively difficult and slow one handed, and may not stop the bleeding with large wounds. Also, bear in mind a gunshot wound usually has an entry wound and an exit wound. It would be very difficult to bandage both wounds properly and quickly, especially with one hand. With a tourniquet, it doesn't make much difference that there are two wounds.
The speed with which you stop the bleeding is very important. I couldn't find a reputable citation with a quick search but with femoral arterial bleeding it seems generally accepted that it's possible to bleed out in under 3 minutes, and to lose consciousness well earlier than that.
- They are effective in preventing blood loss in most extremity wounds (wounds to the arms or legs). Extremity wounds comprise the majority of traumatic injuries in US armed conflicts. See http://www.ncbi.nlm.nih.gov/pubmed/17414553
Extremity wounds are easier to self-treat than torso or head wounds.
- They are very light and compact (about the volume of two fingers, and weighing about two to five ounces)
- They are inexpensive. The CAT or SOFT-T can be had for about 25 to 35 dollars.
- You can train with them to some degree without using them up. You can practice putting a tourniquet on without worrying about wearing it out or getting it un-sterile. Obviously if you put a tourniquet on 100 times, that might start to wear it out, but a certain amount of training is fine. For fast access, you can easily connect it to the outside of your gear or rifle. See the "How to carry tourniquets" section below for more. Compare this to bandages; they must be kept in their sterile packaging so to take one out for training or leave one exposed outside of a pouch would ruin it.
But what about the risk of losing the limb?
The old school of thought was that tourniquets should be a last-ditch solution, and that use of a tourniquet would necessitate amputation of the limb. Recent military experience has shown that modern tourniquets can be in place for at least two hours with a very low risk of losing the limb as a result of the tourniquet. See the links at the end for references.
"A series of studies have looked at the efficacy of prehospital tourniquets and their safety.(16–18) The conclusions are overwhelmingly in favor of applying tourniquets to control severe extremity hemorrhage. In addition, they highlight the near-total absence of significant complications attributable solely to the use of tourniquets. ... Instances of effective tourniquets being placed for up to 20 hours have been recorded with complete viability of the limb and return to full duty."
Which tourniquets?
Specific tourniquets I recommend are the CAT or SOFT-T Wide.
Between the two, the CAT is lighter because it has a plastic windlass, but the windlass is less durable for the same reason. The SOFT-T has an aluminum windlass. I would take the SOFT-T unless you are very concerned about a few ounces of weight, or if you're going through a lot of metal detectors.
The SWAT tourniquet has its place, but consider that it will be difficult to apply one handed, and since it has no windlass, you can't fine tune the pressure that is applied. See also "Risks of Rubber Band Tourniquet Use"
If you're going to carry one tourniquet, you probably should consider carrying two. Your legs are very close together and if someone's taking multiple shots at your legs, if one leg is hit there is a pretty high likelihood that the other will be hit as well.
How to carry tourniquets:
- In a pocket.
- In a medical kit pouch
- On MOLLE: The Blue Force Gear Tourniquet Now! or the Mayflower tourniquet holder. Or you can rig your own using shock cord: http://jerkingthetrigger.com/blog//2010/03/12/tactical-handyman-tournequit-retention-doohicky/
Any closed-top single pistol mag pouch would probably work as well.
Thinking about making sure you can access the tourniquet with either hand in case the other arm is injured.
References:
http://www.cbsnews.com/8301-18563_162-57339769/how-a-simple-tool-saved-many-u.s-lives-in-iraq/
http://www.jems.com/article/patient-care/civilian-ems-should-consider-tourniquets
http://www.jems.com/article/major-incidents/tourniquet-first
http://www.jems.com/article/patient-care/return-tourniquets-original-re
http://www.ncbi.nlm.nih.gov/pubmed/12768129
http://journals.lww.com/annalsofsurgery/Abstract/2009/01000/Survival_With_Emergency_Tourniquet_Use_to_Stop.1.aspx
Subscribe to:
Posts (Atom)