M&P-15 and other ARs: What's the difference?

Rastoff said:
I have to admit, I never thought of the material itself when talking about the upper or lower. I don't think I'll ever be in a situation where my gun is being run over by a truck so, I'm not sure it matters. I know the lower doesn't take a lot of stress therefore, I see no reason to spend a mint on one. Someone correct me if I'm wrong.
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You have to remember. That (lower) is where the buffer and spring are slamming back and forth being hammered by the BCG (Bolt Carrier Group) every time you squeeze a round off. That shock does run through the whole lower too.

You also want all those parts, safety, trigger group, mag release, pins, springs, take down pins to be held and stay in place. Mag well to stay lined with the upper so the mag seats for feeding rounds...

...and chances are, if any MSR gets run over by a truck. It's party will be over.
 
Arik said:
I consider most ARs below TDP to be kinda like shopping at Harbor Freight. Most tools are fine for the occasional do-it-yourselfer. Just to have tools incase some plumbing needs to be done, some bolts tightened...etc...etc....but those same tools are nowhere near the quality steel of say SnapOn or other more expansive tools. And dont be surprised when the Harbor Freight tool breaks or fails before the more expansive one does. There is a difference when a tool is cut and shaped from stock and when one is just poured into a mold.

Why I like TDP is because it tells me this. I can choose to go higher but I know where I stand
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So then.... YOU have a copy of the TDP???:confused:

That would be rather amazing, because during the last series of ICR tests (Individual combat rifle) even competitive companies like Sig Sauer, LWRC could not get THEIR hands on a full TDP. They had to reverse-engineer the existing rifles which were samples, and go from there.

And in the end, Colt is now???3rd place. Remington won the .mil contract, Colt cried over the loss of said contract, and FN took the contract on the rebid. Linky: http://kitup.military.com/2013/02/army-awards-m4m4a1-contract-fn.html

Down the wormhole. The M249 SAW uses a 4140 barrel. :p So unless one would expect to subject their personal rifles to that kind of punishment, I'd say it were a stretch to throw about the idea that the difference between the 2 materials is so great as to warrant an immediate dismissal of one over the other.

There are no rifles completely made in house by one manufacturer solely. Everyone is subbing out for parts. All this has been gone over before. The differences in many of the parts is the level by which the parts are tested.

As to the query on polymer lowers? I am not that interested. They have proven to crack time and time again under relatively low cycling counts. The bolt movement is such on an AR that there is more stress than a Glock will ever create on it's contact points. If one were to get an 80% for dirt cheap ($25ish) then it would be worth milling one out and keeping it for a rainy day or for making a 22lr out of it.

I'm going to stay in camp with Cypher and JaPes, and go with what I have, shoot it some more (16K rounds seems like a lot, until you really think about it, and then you say "That IS a lot!" So, the Sport is pretty well vetted at this point) but if I can figure when it hits the 20K mark I will throw a party.:rolleyes:
 
Rastoff said:
I have to admit, I never thought of the material itself when talking about the upper or lower. I don't think I'll ever be in a situation where my gun is being run over by a truck so, I'm not sure it matters. I know the lower doesn't take a lot of stress therefore, I see no reason to spend a mint on one. Someone correct me if I'm wrong.
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The front pin area takes a beating and is known to be a stress point which cracks, and the rear pin hole has some tendency to oblong and guys tend to use anti-walk pins over time to keep the pins in. The buffer tube neck has a tendency to crack, and believe it or not, I tinkered on one a month ago which literally was super-glued there.... and still limping along. A spectacular advertisement for super glue..... not so much for a BM Carbon lower.
 
I wouldnt say its a copy. Its just missing the select fire and a shorter barrel, which i can legally get in my state. Yep and if the worst company followed TDP I'd buy that too, cause it would be no different than Colt. Until then I don't see where the savings are. I can buy used Colts for about the same price as M&Ps. My last Colt cost me a whopping $670

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Arik said:
Yep and if the worst company followed TDP I'd buy that too, cause it would be no different than Colt. Until then I don't see where the savings are. I can buy used Colts for about the same price as M&Ps. My last Colt cost me a whopping $670

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Yup. The after affect of panic buying on credit. Some bought just to have one before they got banned. Some bought multiples on credit hoping to pull off a post ban sale profit similar to pre 1986(?) full auto firearms.

The best time to buy is after a panic. Credit bills come due, used rifles glut the market bringing down the prices of both new and used rifles.
 
rojodiablo said:
Down the wormhole. The M249 SAW uses a 4140 barrel. :p
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I don't know for sure, but I had read somewhere that the SAW uses the same steel as the M4, but the chrome lining is twice as thick.

Noveske made some AR barrels this way...
 
Arik said:
I wouldnt say its a copy. Its just missing the select fire and a shorter barrel, which i can legally get in my state. Yep and if the worst company followed TDP I'd buy that too, cause it would be no different than Colt. Until then I don't see where the savings are. I can buy used Colts for about the same price as M&Ps. My last Colt cost me a whopping $670

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When rojodiablo referenced a "copy of the TDP", he was asking if you had access to the documents that make up the TDP, not if your Colt was built to the exact standards of TDP.

There are very few companies that have access to the TDP to build to, and of the ones that have access, they can only build to that specification for govt. rifles. They can not use that same set of specs to build for the commercial market, because Colt holds the license. For example, look at the FN AR that just hit the market. Folks are complaining that it is not "mil-spec" and it is not "built" to TDP. FN has access to TDP to build rifles for Uncle Sam, but they can not use those specs to build a rifle for the commercial market.

As far as prices for used Colts vs. new S&W, apples and oranges. You can't compare the two.
 
So you're saying that Colt makes 2 different variations? Instead of making one lower/upper/whatever. ...they make 2? One for gov and one for us? But the one for us is made of different raw materials?

I don't see how it's apples to oranges. I'm buying the best for my money. If I need a car I buy the best for my money, new or used.

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Arik said:
So you're saying that Colt makes 2 different variations? Instead of making one lower/upper/whatever. ...they make 2? One for gov and one for us? But the one for us is made of different raw materials?

I don't see how it's apples to oranges. I'm buying the best for my money. If I need a car I buy the best for my money, new or used.

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No, Colt owns the license to TDP, so they can follow their own specs... but in actuality, they have made two variations in the past.

And we will just have to agree to disagree if you think Colt is the best for the money, new or used.
 
You're buying what you consider to be the best for your money given the depth and breadth of background information available to you.

Colt owns the rights to license the TDP. The patents for the AR-15 platform have expired, so anyone can make an AR-15, M16, or M4. Any company producing a M4 under government contract must meet the TDP, and pay Colt a fee for every rifle produced. People assume that since Colt owns the TDP, they build all their AR-15's to TDP standards. Some assumed that the LE6920, which was once only available to law enforcement, was built to TDP. It followed the flawed assumption that law enforcement had to have same as the military.

Colt can claim to build their civilian rifles to TDP, but there is no way to independently verify the claim because the TDP is secret. That's my issue with those that place all their faith in the TDP allowing it to override common critical thinking skills. I think of it in this hypothetical conversation.

Colt Rep: Yep. This rifle is TDP all the way. Look at the bolt and you can tell.

Customer: Really? Can I review the TDP to assess the validity of that claim?

Colt Rep: Sorry, you can't. It's Top Secret. You just have to trust me on it.

Change that conversation to one buying a car. Imagine wanting to buy a car and the salesman can't back up their claim of fitness or use, but asks you to just trust that what he or she says is true.

It's my opinion that Colt's brand image and the general assumption that Colt builds civilian rifles to TDP, is why Colt rifles can command a slightly higher price than a similar rifle manufactured by a competitor. The prancing pony roll mark is marketing gold.

At least Colt is a long established firearms manufacturer who can backup warranty and service claims. Everything else aside, this is a good thing for a newbie buying their first AR-15. I think we can all agree that for a newbie AR-15 buyer, the best general advice is to buy a factory complete rifle from a well known and long term established manufacturer that has the resources to back up their warranty.
 
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It just doesn't make sense that they would spend the money to basically make the same thing but with different materials. I can see if it had a different finish but that's it. All other manufacturers that make military small arms don't do anything different for the civilian market. They might have different stocks but the rifle is the same.

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Arik said:
It just doesn't make sense that they would spend the money to basically make the same thing but with different materials. I can see if it had a different finish but that's it. All other manufacturers that make military small arms don't do anything different for the civilian market. They might have different stocks but the rifle is the same.

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Look at FN... they currently make the M4 for the military. If you compare the military FN and the one that is marketed to civilian and law enforcement, you will find differences, such as:
1. Civilian version does not use 7075 aluminum for the receiver extension.
2. Civilian version does not stake the castle nut from the factory... military version is staked.
3. Civilian version uses a carbine weight buffer, military version uses a heavy buffer.


Back to the used vs. new, best for your money... Do you have any idea how many rounds have been fired? Do you check head space and throat erosion? Or measure the erosion at the gas port?

With a new rifle, I don't have to worry about those things. As long as I go with a rifle from a reputable manufacturer with a history of QC and standing behind their product, most any AR is going to meet my needs.

Colt makes a good rifle, and now that Colt is again competing in the civilian market, their rifle has dropped in price. If a $900 NIB Colt LE6920 was available at the time I bought my Sport, I may have went in a different direction.
 
As I said before, I hadn't heard of TDP before this thread. Personally, I don't give a rats patootie about some government TDP. It's just a set of requirements. Top Secret? Really? So what? As long as a company builds a gun that will do what they say it will do, who cares about anything else?

I mean, my Savage is much more accurate than any AR I own. It wasn't built to some government standard; it was built to Savage's reputation. That means it's going to be a good rifle right out of the box because Savage has built their reputation on that.

I don't care if my AR is built to some anonymous standard. I want it to hit the target I aim at. So far, all the guns I have are more accurate than I am. They're more durable than me and all work harder than I do. What more can I ask of a tool?
 
Arik said:
It just doesn't make sense that they would spend the money to basically make the same thing but with different materials. I can see if it had a different finish but that's it. All other manufacturers that make military small arms don't do anything different for the civilian market. They might have different stocks but the rifle is the same.

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You might not be understanding what is done via production. The lowers Colt uses are made by a company who makes lowers for several other rifle manufacturers, including Stag, LMT, and a slew of others.
The uppers? Same thing. Stag arms makes a lot of the triggers and magazine catch assemblies, used by S&W, Colt, and take your pick of who else.
The lowers are forged en masse, and the final machining is done in house by each maker.
What makes a true 'Mil Spec' part in and of itself is the type of test done on the parts, and the frequency of those tests. Whereas a single barrel, trigger, or buffer might get tested out of a daily production run and that is 'batch tested', there is a larger scale in which a weekly run or daily run might be tested. For the TDP, we do not KNOW how frequently they are tested, we simply know the test is likely much more frequent than a non .mil unit, simply because it is not necessary. (The amount of destructive testing adds a lot to the cost of the rifles. Materials all being equal, when you are doing destructive testing on 10% of the production....... that kind of testing adds serious cost to a given production.)

Many, many of the parts..... are the same. The questions are in what level of testing and types of tests performed.
I am NOT saying Colt does not do a bang-up job on making their AR's. It's pretty well understood, they do not cut corners, and it is appreciated by folks who will pay for that peace of mind. On the other hand, this does not exclude any other manufacturers specifically from saying they are not delivering quality products. (We can all agree that Plum Crazy DOES deliver garbage, but thats' a whole other thread!!!:D )

In the end, what it all means to ME is........ I am sure glad S&W followed standard protocol on the M&P15 series, and they have a very good record of dependability and function.
I just wish they had done the same with the M&P10. Talk about snatching defeat right out of the jaws of victory........:(
 
Colt LE6920 are ok... but the great thing about ARs is that you can choose anything and everything just they way you want it. The only thing about a LE6920 that must remain Colt is the serialized lower. So you can pretty much fix everything else. ;)
 
The difference in actual performance between a 2k AR and a decent sub 1k gun can be shockingly little. The higher end gun will survive full auto better and barrels and bolts may last a bit longer. I stick to mid grade guns with accurate (rather than multi chrome plated and exotic metals) barrels.

I still have my MT6601 of 90's vintage with some minor upgrades. It continues to perform and impress. You won't see me on arf.com fighting over rifle specs.

I've built two to my specs with a mix of budget, mid grade, and high end parts based on my preferences. They're both awesome.

Pick one you like, with features you prefer, and a price you can live with from a reputable manufacturer.
 
Technically it's Stoner gas operation vs conventional gas piston.

The Stoner system is not D.I. as the expanding gas is contained within the bolt carrier and the bolt itself is the piston. The original patent even differentiates it from D.I.

The op rod short and long stroke systems kind of undo the entire concept behind the in - line design.

The piston guns contain fouling separate from the bolt and hold lubricant better in the operating parts. IMO unless shooting over 1k rounds at a time without lubricating the rifle it's going backwards.

Several individuals and carbine training school personnel have proven that merely keeping the bolt and carrier lubricated will keep an AR running into tens of thousands of rounds without cleaning.

A few companies offering such rifles build some high quality examples, but I see the op rod piston guns as lazy man's rifles, and a step backwards on the principal behind the original design.
 
:rolleyes:You guys and your acronyms.:rolleyes: D.I.? Digital Indexing? Oh, wait, I see it now, you meant to type DGI for direct gas impingement.

I find it odd that this stuff is even a discussion amongst AR guys. Both types are exactly the same. It's just the placement of the moving parts.

Yes, the 'piston' style guns exhaust the gasses at or near the gas block where the older style exhaust the gasses back at the bolt. I've seen both in operation. Both seem to shoot and cycle just fine.

The reality is that both are gas operated guns. That's why I asked the question. I have yet to see a recoil operated AR.
 
The difference between DI and Piston is that with a piston hot dirty combustion gasses aren't being blown back into the action. Fouling still occurs in a piston gun, confined to the piston cylinder. Both get the job done. I give a nod to the traditional direct gas impingement system because it's standardized. Gas piston systems are different from manufacturer to manufacturer.

If I want a gas piston operated rifle chambered in 5.56 NATO, I'll get a platform originally designed as a gas piston system: Ruger Mini-14, FN SCAR, FN F2000, Bushmaster ACR, IWI Tavor, etc.
 
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