AR/M4 Durability

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Actually the AR-15 was very reliable when our military began buying them from Colt. Then the military began using the wrong powder in ammo, poor magazines along with poor training and maintenance. Then it was rushed into a jungle war with a non-chrome lined chamber and bore. And no cleaning kits. Most of the AR/M16 problems reported in Vietnam weren't due to the rifle itself.

It is true the M16 evolved into a better rifle over the decades but the first ones were pretty darn good.
 
I don't argue that there has not been some improvement on the execution of the design over the years. That said, take a colt decades ago and don't maintain it and it will have problems. Take a colt made today and fail to maintain it and it will have problems. If you tell people they don't need to clean, and more importantly lube guns, they will not work for long. Pat Rogers has said that his experience is that good ARs will tend to stop functioning well within a few hundred rounds without lube.
 
Are you going to run more than 5000 rounds through it in your lifetime? 10,000? Because that's pretty easy to do in a few seasons if you 'run it'.

If you are just going to ocacsionally plink with it it will last a lifetime. If you are going to run it hard you might want some spare parts. Those are currently tough to get but that will change.
 
Actually the AR-15 was very reliable when our military began buying them from Colt. Then the military began using the wrong powder in ammo, poor magazines along with poor training and maintenance. Then it was rushed into a jungle war with a non-chrome lined chamber and bore. And no cleaning kits. Most of the AR/M16 problems reported in Vietnam weren't due to the rifle itself.

It is true the M16 evolved into a better rifle over the decades but the first ones were pretty darn good.
Excuses.

Still evolution out of failure. Not sure why its defended or excused. It's not necessary, as what you have today it a smattering of contingents put in place to handle the little what ifs, and voila! Better rifle.
 
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I don't argue that there has not been some improvement on the execution of the design over the years. That said, take a colt decades ago and don't maintain it and it will have problems. Take a colt made today and fail to maintain it and it will have problems. If you tell people they don't need to clean, and more importantly lube guns, they will not work for long. Pat Rogers has said that his experience is that good ARs will tend to stop functioning well within a few hundred rounds without lube.
And yet, there is still a more reliable rendition of that rifle today, no matter what you want to call the reasoning, or what you want to blame. Crappy, corrosive ammo is to whom I send a thanks daily that my AK variants wear chrome. Or was it soldier neglect? No matter, I don't try to defend the platform, it is what it is.

It's still a better rifle that evolved initially out of failure.
 
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ARPerformance barrel and super bolt. Nickle Boron carrier. Your great, great, great grand kids will still be shooting it. End of discussion.
 
Yes. building. I have a psa multical lower. I put in a match grade trigger fro RRA. Wasn't necessary, but I do like the weight.
I'm leaning towards a BCM or LMT upper with a Colt barrel. just have to find the rightt deal.

Okay guys, as I see it, the benefits of Colt are that they are mil-spec and have the most experience building them so you have a good assurance that they are quality. So the arguments about Colt's evolution and all that, while interesting, don't really seem pertinent since the OP is building. I don't think Colt PARTS are inherently better than anybody else's.

The OP just needs the BCG and barrel components. Not sure if he also needs the receiver. If so, I'd say don't worry about brand-recognition with that, it's not as important. The BCG is the place to splurge. Nickel boron or any of the new fancy coatings definitely will slick it up and you can use less lube allegedly, but you still need lube! I have seen some BCG's trickle back into stock, but they are all semi-auto and for a carbine I think you'd definitely want the full auto carrier.

I agree with JustinJ that Colt probably makes a fine barrel but you would do just as well with BCM or PSA CL barrels. And then you could do midlength gas system and probably be fine with a semi-auto carrier. Plus, mid-lengths are all the rage these days! ;)
 
Gotta have the rage. :evil:

Just ordered a BCM Lightweight Carbine upper. No bolts/carriers available though. Sold my RRA middie recently. I don't really buy into the coolness or necessity of the mid-length gas thing. YMMV

M
 
Are you going to run more than 5000 rounds through it in your lifetime? 10,000? Because that's pretty easy to do in a few seasons if you 'run it'.

If you are just going to ocacsionally plink with it it will last a lifetime. If you are going to run it hard you might want some spare parts. Those are currently tough to get but that will change.

This.

Mine has 2,070 rounds through it since June, and I limited my round count due to the cost of ammunition. Own it for several years at that rate, and spare parts become important.

For spares I currently have: A complete bolt, a set of gas rings, a set of all springs, a set of all pins, a DPMS ultimate repair kit (don't laugh, it has lots of stuff in it), a buffer spring, a FCG (fire control group, or 'trigger') a buffer, a firing pin, and a cam pin (and maybe things I forgot about).
 
PSA shows 14.7" carbine barrels in stock right now on the website. They've had uppers in stock recently as well, though I haven't been impressed with their spray-on finish. The BCG is going to be the hardest part to find at the moment. If you're not in a hurry I'd keep an eye on BCM's site and order a complete upper from them.
 
Gotta have the rage. :evil:

Just ordered a BCM Lightweight Carbine upper. No bolts/carriers available though. Sold my RRA middie recently. I don't really buy into the coolness or necessity of the mid-length gas thing. YMMV

M
It's not about coolness or neccessity. I'm not sure where you're getting your information. The midlength gas system offers a softer pulse, possibly less felt recoil, and longer sight radius (using standard FSB.) Please don't be one of those people that poo-poos an idea or concept just because you didn't think of it, aren't familiar with it, or just "because the kids are doing it."
 
^ Truth. A 16" midlength gun (especially with a Battlecomp or Gunfighter comp) has significantly less felt recoil than a standard carbine. You also have more real estate for whatever you're going to hang off of the front and the ability to extend your support hand further out to help drive the gun without having to get a specialized rail to account for the FSB.
 
Gotta have the rage. :evil:

Just ordered a BCM Lightweight Carbine upper. No bolts/carriers available though. Sold my RRA middie recently. I don't really buy into the coolness or necessity of the mid-length gas thing. YMMV

M

Mid length offers many advantages over a carbine length gas system.

But hey, that's okay, you bought into all of the rage and coolness by selling your RRA to buy a teir 1 true operator spec ultra badass BCM, you'll get your real SEAL team 6 operator stickers in the mail shortly
 
Mid length offers many advantages over a carbine length gas system.

But hey, that's okay, you bought into all of the rage and coolness by selling your RRA to buy a teir 1 true operator spec ultra badass BCM, you'll get your real SEAL team 6 operator stickers in the mail shortly
I've argued this point before on other forums. Differences are miniscule. Show me some proof that simply adding a H2 buffer won't do the same thing. Sight radius? Meh. I can shoot MOA with carbine irons and that with corrective lenses on 62yr old eyes. Accessories for midlength aren't nearly as available for middies. And Colt worshippers, why doesn't Colt make one? Just sayin'...

M
 
I just made a joke about the middies. Although they are more popular right now, I think most of that is due to the "trendiness" of them. At that, m1key has a point. A good carbine setup with full auto BCG and H2 buffer should be just fine. Although I have a hard time believing anyone can consistently do 1 moa with carbine irons. I can barely do 1" at 25 yards much less 100.

That said, I do enjoy shooting my middie. It is definitely softer recoil although that could also be attributed partly to the heavier-profile barrel. And for open sights, way more precise than the carbine. Some people like the "look" of the carbine, others like the middy, I think both look nice.

How this all relates back to the OP, is that, in theory, a middy will be easier on parts in the long run (more perceived durability). But, I don't know if anyone has taken identical setups with everything the same except the gas length and did a torture test to prove it.
 
I built a AR for my wife using a BCM lightweight barrel with mid length gas. The rifle is 7lbs unloaded with optic and it's still softer shooting than any carbine gassed AR I've tried.

Unless I was doing a SBR I'd personally avoid the carbine gas set up. It's just too violent.

BSW
 
Although I have a hard time believing anyone can consistently do 1 moa with carbine irons. I can barely do 1" at 25 yards much less 100.

With military ammo? Heck no.

Try some of this out of a Colt 1:9 lightweight barrel with Colt factory match trigger:

Sierra 52 Match
23.0gr Accurate 2015
Federal match primer
Winchester or Federal brass

Off a pair of good bags, rested just ahead of the magwell, no wind, slow fire.

I'll bet you can do it...

P.S. take that blocky front sight, chuck it up in a variable speed drill, make a nice fine point with a file. A drop of BLUE locktite will ensue it's tight. Use the smaller aperture...

Good luck

M
 
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I can shoot MOA with carbine irons and that with corrective lenses on 62yr old eyes.

bsflag.gif

Maybe you just don't understand what MOA means.

Accessories for midlength aren't nearly as available for middies.

I just really think you are functioning 15 years ago.

At least you dumped your RRA in favor of a BCM. Say, um... so who do you think the 3 most knowledgable people associated with BCM would be on the subject of AR15s. I would say Pat Rogers, Paul Baffoni, and Travis Haley, but that's just my opinion. So, here is some info from them about midlengths:

http://www.youtube.com/watch?v=yU8ryJN9E5s&feature=player_embedded
http://www.bravocompanyusa.com/BCM-M16-A4-AR15-Bravo-Company-carbine-EAG-Pat-Rogers-s/151.htm
http://www.bravocompanyusa.com/BCM-M16-A4-AR15-Bravo-Company-Haley-Strategic-The-Jack-s/166.htm

A little google search could provide you more. At this point I'm pretty sure that I'm shoving the horse's head into the river.
 
I stand in AWE of your proof. :neener:

What I see is three Youtube advertisements for BCM products.

Let's hear exactly what your "pros" have to say...I mean like raw data.

How many fanboys are gonna lay out the cash for enough ammo in to prove the durability of their middie M4.

M
 
Off a pair of good bags, rested just ahead of the magwell, no wind, slow fire.

I'll bet you can do it...

P.S. take that blocky front sight, chuck it up in a variable speed drill, make a nice fine point with a file. A drop of BLUE locktite will ensue it's tight. Use the smaller aperture...

Good luck

If you say so. Consider me impressed. I have been meaning to file down the front sight on the carbine. That standard post is just too big. However, I suppose it is just backups to the red dot and if I am using irons then a lot of other stuff has already gone wrong and I don't need ultra precision. That is pretty impressive though, still.

BSW, I wouldn't call the carbine "violent" by any means, but it definitely doesn't gently kiss your shoulder like a rifle or middy. So, as everything is relative, a carbine gas system will beat up the internal components a bit more, as well as your shoulder.
 
My camera just died or I would post pictures of the rifle. I will admit the groups were shot a few years ago. As soon as the dang wind quits blowing, I'll try to shoot some more groups.:cuss:

The carbine has since undergone some Magpul mods and a tritium front sight since it's now my HD gun loaded with Black Hills 68gr HPs.

M
 
Gas port closer to the chamber causes increased bolt/bolt carrier velocity and a sharper recoil impulse and increased wear on the operating system vis-à-vis rifle length gas.

Your raw data will be the lifespan of bolts in military service.

Look it up.
No, you look it up. I'm too old to care. Has the military been using H2 buffers all this time? Is the military going to middies now? For civilian use (none FA) I still maintain there is too little difference to bother with. Maybe we'll know for sure in another fifty years, but then we'll all be dead.

M
 
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as for shooting MOA with a carbine, it is possible, but the key isn't necessarily a smaller front sight post. it is very difficult for old people to focus on the standard front sight post on a rifle length gun. it would be even more difficult to focus on a shaved one on a carbine length. that is why many high power shooters replace their standard front site post with a wider one when they pass 40 years old.

no, the key would be selecting an appropriate target. as long as you have a consistent sight picture, you can shoot MOA. You just need to make the target a big black circle, or some other high contrast, black/white type image where you can put the front sight post in the same spot each time. you could even make a U shaped black spot that just shows a line of white when you put your front sight post in it.

Show me some proof that simply adding a H2 buffer won't do the same thing.

think about it from an engineering standpoint. if you need to build a pneumatic system (or, maybe compressed air, or CO2) and a cylinder to blow a piece of metal back at a certain speed (not too fast, not too slow), would you rather use high volume of gas at a lower pressure? or a low volume of gas at a higher pressure?

cause that's all we're talking about.

this image is from randal (ar15 barrels)

223plot.gif


you can see, there IS a very big difference in peak port pressure between carbine and midlength. as an engineer, you would have to compensate for that difference by varying the size of the hole (and location which controls dwell time) to allow more or less gas in.

but effectively, you're going from what was a relatively higher volume at a lower pressure on the original rifle length M16 to a lower volume at a higher pressure on the carbine.


so to say that changing the gas tube length, port hole size and dwell time are the same thing as changing the buffer weight is wildly inaccurate.

changing the buffer weight changes the amount of mass reciprocating, which means it slamming into the stock and then slamming back into battery (along with the usual 3rd bolt bounce impact) affect user perceived 'recoil' and your ability to keep the gun pointed at the target for a follow up shot.

if you want soft recoiling, do like JP rifles did and use a light weight carrier for less reciprocating mass.

the reason for adding weight to the buffer is that it delays the bolt coming out of battery. when you have a shorter barrel, as you can see from the graph when the bullet exits the barrel the chamber pressure is still VERY high. this commonly causes failure-to-extract because the brass is still sticking to the chamber walls. adding weight gives you a few milliseconds for the pressure to go down before opening the bolt.
 
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