Re: AR-15; the progeny of genius.
Posted: Wed Jun 14, 2017 10:20 pm
Here goes - another serious discussion!
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Nitroex, Sorry it has taken so long to reply but pressing family matters and life in general got int he way.nitroex700 wrote:@xl_target:
Dear Sir,
First, sorry for the delayed response. The laptop had gone kaput and took some time.
Second, I am writing my comments under the presumption that you're a retd Indian Army soldier enjoying his life abroad and are not associated with the weapons business. Out of respect for the Fauj, I will put forth my arguments against yours. However I sincerely hope that it shall not start another 'limited war' on this forum over who is right, as that is not the intention.
Third, if either of my assumptions is incorrect, pls omit the rest of my response.
Every new shave tail lieutenant to General officer wants to leave his mark on his service. He wants to do his best for his men and get them better equipment. That's just human nature. It might be illuminating to note that even with the many service rifle competitions, the M16 is still in service, so many years after its inception. What a soldier requires in a weapon is for it to go bang every time he pulls the trigger and it must give him a chance of hitting his target if he does his part. If it continues to do that, you've got to have something significantly better before you can justify a change.That makes me wonder about their true intentions behind their constant squirming to 'modernize', since you're just dumping one AR15 to buy another one.. perhaps it suits the interests of the mighty arms industry well represented by many in their brass...xl_target wrote: You're correct that nothing really ground breaking has happened with the design since Stoner invented it.
Changes have been minor and the basic design has remained the same.
In fact, one could take the upper of a Vietnam era M16, slip it onto a lower purchased last week and it will function with very few issues.
I submit that it is the soundness of Stoner's design that is reflected here and nothing else.
IMHO the best operating mechanisms for assault rifles are short stroke pistons and delayed blowbacks - but then I am not as knowledgeable as many others.
Ah, the myth of the Mattel toy that didn't work.Pls tell why do they have a forward assist and dust covers if they're indeed so flawlessly reliable? If I remember correctly they first started jamming with dust and grit in Vietnam and have continued to so sincerely ever since.. A warfighting weapon must be 'element proof' IMHO. Again, I may be wrong.Two Gulf Wars, a war in Iraq and one in Afghanistan have shown us that there is nothing unreliable about the DI guns out there.
Lets talk about killing potential. When the Marines went to Fallujah with their ACOG equipped rifles, there was a huge increase in headshot insurgents. So much so that it was thought that the Marines were executing captured insurgents. An investigation proved otherwise. Marines are trained to be riflemen first and are quite proud of their skills. The M4 is accurate enough to use a magnified optic to its potential. Who needs to worry about temporary wound cavity, and all that mumbo jumbo when you can do that. On the other hand 5.56 NATO will produce a wound cavity that is enough to disable or kill.You can achieve good ballistics with lighter bullets in a smaller caliber, however it also quickly brings down its killing potential - those who have used 7.62x39 vs 5.56x45 in a counter insurgency scenario would vouch for this fact. If I ever shot someone where they could shoot back at me, I would definitely want them dead with the first hit.Not surprisingly, in the over 50 years of its use, there is a whole library of documentation about the effects of the 5.56X45 cartridge on humans. People who deride the round as a "poodle shooter" have not seem the terminal effects of a 55 or 62 grain bullet travelling at 3000 feet/sec. Where you start to have problems with the round is at distance. However, I believe the M855 round was designed to penetrate a steel helmet at 600 yards from an M16.
There are ways to achieve the tumble and frag performance of the 5.56 with other rounds as well. However the 5.56 can not create a bigger wound cavity to kill the enemy quickly enough with a single shot to preempt life threatening situations for the shooter. It also lacks the punching power of heavier rounds like the 300 BLK and the 6.5 Grendel.
It suppresses beautifully, with subsonic ammo. Which is great in a shoot house or in CQB. However, then if you want to reach out and touch someone, the same subsonic ammo is not the way to go.IMHO it is an excellent 'counter insurgency round' that can be the best replacement for the 7.62x39. It kills like a 7.62x39, can be suppressed like a 9mm, fired full auto like the 5.56, accurate like 308 and available in AR15.. What more do you want really?Even though the Dutch Special Forces use a limited amount of 300 BLK, it will never be a significant military round.
The beauty of 300 BLK is that it suppresses very well with a short barrel with subsonic rounds. The use of a short barrel and suppressor would make it a good close quarters battle round. This gives you a compact and quiet weapon but those characteristics limit range and energy delivered downrange.
9mm penetrates passes the 12" FBI test from a pistol barrel. At close range, that is adequate. In a CQB application, you don't need more as demonstrated many times by the Israeli's, the SAS and various European anti-terrorist squads. Subsonic is pretty close to a pistol round in its effectiveness.Apart from the suppressed carbine configuration it can also be employed as a very effective 'smg'/SBR cartridge. Its supersonic rounds also display a superior suppression capability compared to 5.56 due to the lesser powder used. They also retain more power than the 5.56 at all ranges. The subsonic cartridges obviously limit hitting power but the gigantic 220 gr bullets are still as lethal as a medium caliber rifle round going subsonic.. The penetration potential of the subsonic round will also be much greater than the 9mm typically employed for such work.
No, the No.1 requirement was that it fit in an AR-15 magazine AND provide more energy at close range.Where it SUPPOSEDLY lags behind the 5.56 is its 7.62x39 ballistics but wasn't it a 7.62x39 replacement in the first place? If you really want the ballistics then 6.5 Grendel is the way forward.
SOCOM gets whatever it wants. They have their own budgets and procurement systems. They field weapons systems that no one else has. Some SF in India use the Tavor, Does that mean every Jawan can now expect a Tavor to replace his INSAS?I believe that the US SOCOM has issued an RFP for ARs in 300BLK chambering. Once that happens, I'm sure that enough heads will turn to make a difference...
People do that, quite commonly, with heavier bullets, in the 5.56X45 (in bolt action rifles). Is it the best choice for that range? Likely not. Can it do that in an accurized AR? Quite likely.AFAIK the US army wants its ARs to shoot accurately out to 1km - best of luck for doing that with 5.56!Loads that deliver supersonic velocities, negate the sound moderation delivered by the suppressor but the average soldier doesn't gain much over the M855 5.56 round. Not enough to necessitate a change.
The various 6.XX rounds offer an improvement but apparently not enough of an improvement to necessitate a wholesale change, according to the military.
ckkalyan wrote:Here goes - another serious discussion!
We are going here.... down the US AR-15 builders rabbit hole.Baljit wrote:ckkalyan wrote:Here goes - another serious discussion!
hummm !! where we going ?
Baljit
Blowback operation.. eh! Must be a pretty fast bullet spitter..xl_target wrote: We are going here.... down the US AR-15 builders rabbit hole.
My club started a pistol caliber carbine division and I decided to build a "pistol" for it.
This uses a basic AR-15 lower receiver assembly optimized to take Colt 9mm stick magazines. The magazines hold 32 rounds.
It uses a Pistol buffer tube and a standard carbine buffer spring assembly. The pistol buffer tube means that there is no way to put a stock on it.
However, a "pistol brace" can be attached to the buffer tube. The "brace" is meant to be braced against the forearm, allowing you to fire the gun with one hand.
According to the BATF, it is legal to shoulder a "pistol brace" but if you put a stock on it, it becomes a "short barreled rifle", which is then subject to all sorts of rules, checks and will cost you $200, if you get approval to possess one.
The upper in the photo uses a 10.5" free floated barrel (the optimum barrel length for 9mm) in 9mm Luger(9 X 19mm).
Most 9mm AR style guns are usually blowback guns. Blowback operation is very simple and can be reliable when tuned properly. There are some instances (like the SIG MPX) where they use a short stroke piston.
Anyway, in blowback operation, you have a heavy weight bolt to provide some inertia which keeps the cartridge in the chamber till the bullet leaves the barrel.
Once the cartridge is fired, inertia keeps the bolt closed for a short time. Once the bolt starts moving backwards, it extracts the cartridge and when it is pulled back far enough to clear the chamber, the ejector acts on the base of the spent cartridge case which ejects it. The bolt keeps travelling, compressing the hammer and the buffer spring as it goes. Then as it runs out of energy, the spring pushes it back up towards the chamber. While travelling forward over the magazine, it strips a new round out and feeds it into the chamber. Once the trigger is pulled, the hammer is released which hits the back of the firing pin. This forces the tip of the firing pin into the primer, firing the cartridge.
Hello Notroex700,nitroex700 wrote:
Blowback operation.. eh! Must be a pretty fast bullet spitter..
How does a pistol caliber carbine differ from an SMG btw?
I wonder what a 'pistol caliber carbine' would look like in 44 Mag or 50 AE..
Blowback wouldn't be suitable most likely, a short piston might fit the bill a lot better..
Perhaps it might look like this:
50 AE Carbine.jpg