And the AR is far less exciting than they would have you believe, with most people able to fire only a handful of well-aimed shots in a minute. So what is it that the beginner should know about the. The first thing is the difference between. To keep it simple, the 5. There are minute differences in the throat the space in the bore where the chamber ends and the rifling starts where wear may be accelerated if one uses higher-pressure 5.
In fact, I doubt that most, if any, shooters would ever be able to tell a difference. In order to ensure that I was getting the most accurate maximum average pressures possible, I contacted the manufacturers of a number of different types of ammunition with the results I had found. Of the manufacturers that responded, none informed me that my maximum pressure results were inaccurate although they were understandably reluctant to disclose their proprietary data.
Summary: I tested. I know most people are interested in this part — and yes, I really did fire 5. I had a friend at the range with me at the time, and he stayed a good ways back when I did so.
I was not concerned about what would happen, and as I expected, the results were not spectacular. However, I was surprised about the results I saw. There was no dangerous spike in pressure from firing 5. While pressures were elevated in comparison to one of the 5. This unexpected difference was also borne out by chronograph measurements, which showed that the Weatherby Vanguard Compact bolt action rifle fired the XM ammunition all of which was from the same lot at a velocity which was higher than the lower pressure 5.
In fact, the higher pressure 5. As my gunsmith friend has told me several times, velocity is a sign of pressure, and this second 5. I have owned approximately sixty AR barrels, with a fairly even distribution of. I have also owned numerous bolt action rifles chambered in. I have fired. Although my results are still anecdotal, I do not recall seeing anything worse than popped primers from firing 5. Popped primers are definitely a sign of excess pressure or an abnormal pressure curve, and should not be ignored.
They can become wedged in some of the more important bits of an automatic rifle, causing it to stop functioning, and while this could be annoying at the range, it could also be fatal in a self-defense situation. Summary: Velocities and pressures for 5.
My greatest concern while researching, experimenting for, and writing this article was whether or not I was putting out accurate information. In order to double check my results, I consulted with over half a dozen industry professionals, all of whom have far more experience in this area than I do. They work for highly respected laboratories, companies, and organizations. S government. By this time Armalite had lost a great deal of money through investing in Stoners AR 10 and AR 15 and decided to sell the rights to his designs.
Colt firearms purchased these rights and continued to pursue marketing the AR In , the communist conflict in Vietnam grew with rapid momentum. The U. S had so far committed a small force to Vietnam to inhibit the socialist movement however the Ordnance department did not have enough manufacturing resources to arm the full force that would soon be required.
To this end U. S secretary of defense Robert McNamara made several major decisions that would dramatically alter U. S Ordnance permanently. The Springfield Armory and production of the M14 rifle was dissolved and rifle production turned over to the private sector. Colt was given the contract to supply the AR 15 rifle to U. S forces without further ado. The rifle was used in small numbers up until when both the war and production of the M16 rose dramatically.
From the very outset of its adoption the M16 was plagued with troubles. Stoner had designed the original AR 15 with a very slow barrel twist rate of which was literally a doubled edged sword. By using a slow twist barrel the 55 grain bullet was only just stable in flight, producing a small degree of yaw.
On impact the bullet would immediately tumble and render a wide, incapacitating wound. This was initially considered a brilliant design premise but some rifles produced too much yaw and were very inaccurate at longer ranges. McNamara ordered that the twist rate be changed to before final adoption of the rifle in This cured longer range accuracy problems but completely destroyed the stopping power of the 55 grain bullet which now poked needle holes through its victims.
Nobody questioned the potential consequences of this move and ignorant of the facts, Ordnance brass continued to believe and promote the M as a highly effective cartridge. Major troubles next appeared in when the M16 rifle was adopted en masse by the thousands of U. S soldiers entering Vietnam. S troops were killed while desperately trying to clear jammed chambers.
Troops were further demoralized when neither the military brass or Colt would look into the problem seriously. Instead, troops were accused of not cleaning their rifles properly which had lead to powder fouling. After continued complaints, both the Ordnance department and Colt representatives eventually began to look at the problem although still with a measure of apathy. The M16 then underwent some design alterations however, the cause of the jamming problem had still not been identified.
A new model M16A1 now featured a chrome lined chamber and bore in an effort to produce smoother feeding. Other alterations were made to the M16, but without any true knowledge of the underlying problem, these added unnecessary weight to the rifle which was now only a shade lighter than the M Ordnance staff discovered that Stoner and ammunition manufacturers had initially tested the AR 15 using extruded stick powder but when the Vietnam conflict exploded, ammunition manufacturers adopted the more readily available ball powder.
The ball powder produced a longer peak chamber pressure with dire effects. Normally upon firing, the cartridge should expand to seal the chamber obturation , then contract and then be extracted. With ball powder, the case was still obturated due to the longer peak pressure.
The ejector would then fail to extract the case, tearing through the case rim, leaving the obturated case behind. In , the U. The news was received with a degree of resentment, especially for those countries who had committed precious resources to the T44 cartridge and rifles.
Nevertheless, as finances allowed, all NATO pact members eventually adopted the 5. Most countries adopted the M16A1 rifle while a few worked with their own rifle designs.
A remaining weakness of the M load was its extremely poor penetration through heavy clothing at ranges of yards and beyond. The Belgium military provided a solution with their 62 grain bullet design. The M16 rifle then underwent a further upgrade to a barrel twist rate to utilize the new load. The new model rifle was designated the M16A2.
Today, the M16 rifle design remains in service world wide. The current model is designated the M16A4 and features a Picatinny scope rail with most M16 rifles now wearing a scope. The 62 grain load is still used by all NATO members however its shortcomings are a continual source of frustration to soldiers engaged in combat.
Nevertheless, current allied military strategy does not require a great deal from infantry weapons. The standard operating procedure SOP used in the war against terrorism is somewhat simple and predictable. Allies are required to locate terrorists, surround the target and provide suppressive fire while awaiting either an air strike or artillery support. For our testing, we looked at a standard M, grain load of Hornady Frontier 5. Admittedly, there are a number of variables at work here.
Chief among them, the consistency of the ammunition is a variable outside of the limits of either rifle. Is that as a result of a tighter freebore space in the Wylde rifle?
A guy named Bill Wylde sought to combine the benefits of the. So he took matters into his own hands and designed one. However, it also has the leade diameter of the. This design allows for tight, controlled gas expansion due to the smaller leade diameter.
However, the chamber angling provides sufficient space to handle hotter 5. Basically, the. This versatility allows you to enjoy the exceptional accuracy of. The one major drawback is cost. A firearm with a. Hopefully, as more shooters become aware of what. In the meantime, any extra cash you fork out in a. This is especially true if you put a bunch of lead downrange. Let your fellow shooters know — share this article using the Facebook, Twitter and other social media icons below.
The more we all know, the better organized and stronger the shooting and hunting community will be.
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