Is a Carbine system going to wear any faster than the Mid Lenght sytem?I guess I am asking will I ever wear it out shooting about 1000 rounds a year?I have read on other sites were its seems to be biased for the Mid lenght.
Jason
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Is a Carbine system going to wear any faster than the Mid Lenght sytem?I guess I am asking will I ever wear it out shooting about 1000 rounds a year?I have read on other sites were its seems to be biased for the Mid lenght.
Jason
Yes, the carbine system will wear "faster" than a middy system. Will you notice it? Not likely. A carbine gas system from a good mfg will last you a very long time.
I will add, "bias" towards the mid length system is like some one saying, "fitness experts are biased because they say more excercise can lead to a longer life." The fact is a mid length gas system is not as rough on internals, but that does not mean a carbine will automatically fail you.
The reality is, there ARE quality mid lengths to choose from.
With that in mind, there's no reason to bother with the carbine system at all. It's an example of poor engineering.
a thousand rounds a year... you probably wont ever wear out any rifle, carbine or midlength, shooting a 1000 rounds a year.
The carbine length gas system puts more pressure on parts, so yeah, you could say it wears faster.
To what extent, who knows. Your typical off the rack M4 will digest a hell of a lot rounds before giving up up the ghost. Same for the middy
More than anything else, I would say it is preference. I could go either way personally. Both are sound if you buy right.
You're not likely to wear out either one, but mid-lengths are just a product of better engineering. The biggest advantage of having a mid-length is that their recoil is softer than that of carbines. You also get a longer sight radius.
I'm an owner of a carbine length gas system rifle...I shoot 1000 rounds a month. Coming up for about 18 months of that now, and its not worn out yet, so at 1000 rounds a year, I think you'll be good for a while... ;)
That said, if you don't already own a carbine lengthed rifle - as the others have said, there really is no point in ever choosing that over a middy (in a 14.5 or 16 inch barrel....shorties obviously excepted). When I have to rebarrel mine, I will be putting a mid length on there.
even if you dont get near the wear limits of either, 2 more inches of handguard is a heck of a lot more comfortable.
I was just about to say THIS.
There are hundreds of thousands of carbines out there which has proven themselves under the harshest conditions.
Is a middy better...yes...noticeably...maybe...but like myself and others have stated in carbine -v- middy threads before, has the quantitative testing been done to determine if there is a statistically significant difference? At least not yet.
It will be a helluva long time, if ever, before middies out number carbines.
I think it's pretty easy to demonstrate the principles that support the concept - shorter dwell, delayed extraction, lower gas volume, lower bolt speed, distance and arc of ejected cases, etc., can be observed and measured in a midlength. given these factors it's logical to assume lower stress to the parts of the mechanism.
I know you are asking for empirical testing that compares something like a large quantity of middies vs. CAR firing same ammo in same conditions and evaluating failures but do we actually have to do that to be able to infer, scientifically, that one is more longterm reliable than the other?
I mean, no one really knows what the atmosphere of Saturn is made up of but through radiographic spectral analysis, we can take a pretty good guess, right? ;)
I didn't really want to turn this into yet another science debate, I just wanted to point out that things that people have a tendency of going around spouting as if ffact are too often things that they are only repeating.
and yes, I'd still like to see someone quantify all these claims in some way other than grainy high-speed video.
and I'd also like to know if "stress on the parts" is considered to be high enough to be cumulative and if that cumulative stress really matters in any meaningful way. After the whole debacle of the HPT debate it's clear that many people have just enough knowledge of things to be dangerous and perhas too much to be willing to ask questions.
I have a POS Bushmaster 14.5" carbean upper with like 30k rounds through it. It still head spaces ok, and will hold under 2" groups at 100 as of last weekend.
If you're shooting only 1000 per year... you'll get at least 30 years useage out of it.... give or take. :p
This thread is a big relief to me. I just purchased a ddm4 carbine about 2 months ago. I was sure that I had bought the best carbine in my price range until I started seeing the craze for midlength systems. I found thinking that I may have made the wrong decision and maybe should have bought a midlength carbine. I am new to the rifles and am trying not to get too caught up in the newest coolest shit craze. I almost bought a new lower to build a midlenght m4 recently but now I think that the money would be better spent on ammo and learning to shoot the carbine length system I have. I will probably shoot no more than 5k next year and I am sure the ddm4 will serve me well.
ive got just over 500 rounds in a day thru my dd carbine with not one failure. mixed ammo wolf and brass cased fedral
Careful with that combo. Mixing steel and brass ammo in the same shooting session, without a thorough chamber scrubbing, is a recipe for getting a stuck case. You can get away with it with true 5.56 chambers, but not so much in 223 chambers, but it can still happen. Definitely don't do that in a class. It will be an exercise in frustration when stuck cases suddenly repeat over and over again.
that was one of the reasons i did it. it ran the wolf flwless. so i said lets mix it up. its the new polymer coated stuff and my dd barell is stamped 5.56. but it ran great
I'm seriously investigating the mid-length system, but the carbine AR is a known quantity with years of service and the mid-length is not. Logically, it sounds like the mid-length would be more durable and reliable, but then again maybe not. It's still not a full length gas system. Maybe the mid-length rifle's bolt lasts 3,000 rounds longer than a carbine's bolt? Maybe it's a negligible difference? Until I see some actual data I say it's a matter of preference also.
Run your carbine with a LMT enhanced bolt, H buffer and M16 carrier, change cam pin from time to time and your carbine will outlast a middy with a standard bolt, car buffer and semi carrier by a lot. Parts play a larger role in durability. I guess a middy with good parts would out last it but the barrel would be shot out before this happens.
IMO gas port erosion is the big killer for ARs in general.
I don't understand why when making barrels really short manufacturers don't go ahead and modify the dwell time on the carrier. For the same effect of carbine vs mid gas sytem and the impulse delay, you can add this to to the cut in the carrier in the "dwell" time to get the same effect. You have to be careful because soon the extractor pin that is held in by the bolt group begins to stick out when the bolt is forward but then you just have to step this to keep it in while the bolt is sticking out of the carrier. That is if you go that far, just add enough dwell time to keep it retained and see what that gets you. :big_boss:
no, people are doing it now, just not advertising it,
this is done on the shrike AR style system, it doesn't change much of anything in the end. you can see it more upclose under the industry section in ARfcom.
On that system notice the stepped pin, that is because of the huge dwell addition. You can split the difference and not have to do that.
Not a different system at all, just a small tweak
**Did you know(this could be wrong) that in the beginning(stoner days), they didn't put a dwell in carrier, immediately noticed an issue and a dwell was added, it certainly wasn't tweaked when they shitcanned it to make the M4.
I have a few questions.
The fellow over at 03designgroup has mentioned he has cut his carbine gas system rifles down to 14.5 and his middys at 16 so they have the same length of barrel forward of the gas port. Is this the key to the middy vs. carbine debate?
Also vuurwapen blog mentioned how Colt's 16 carbine gas system guns had bigger gas holes in the barrels than their 14.5 counterparts. Is this something we need to account for, gas hole size?
I remember Ken Elmore before he left Colt in my AR-15 armorer's course discussing the gas system at the end of class. He wrote up on the board some thing like this:
__________A_____________/\_______B___
A being the part of the barrel before the gas hole.
/\ being the gas hole.
B being the part of the barrel forward of the gas hole.
Ken said if you change one of those you have to change the others otherwise you are going to have problems. It was part of his warning to us not to cut barrels down without having someone do it who really understood how changing one changed the others. He was really talking about changing B. He pointed out that the Commando, M4, and M16 gas ports went big, small, and big. Commando was big because it needed gas now, M4 small because it had time with a longer B, and M16 big again because it needed more gas for the long A.
The question I have besides the one above is how does changing A 2 inches forward in a 16 inch gun affect /\. Does /\ need to be bigger or smaller? What about taking a 16 carbine and cutting 1.5 inches off of B?
it's not about set lengths, its about ratio. the gas port should be about 5/8ths of the way down the barrel from the bolt face.. .625% gas to .375 dwell, or something close to that.
gas port size is more complicated.. but as you said, short dwell- larger port.. over-dwelled, shorter port.. longer system, larger port.
unless you're sabre.. then you just use .080 for everything.
This is correct, I was unaware that it was public knowledge for LMT with their carrier. More Dwell is in no way harmful, at all. It makes up for many situations gone bad because of unlock timing and pressures. I wish this was pushed more as a solution that should be implemented on all AR brands, it is only a change in the 4-AXIS CNC program cutting the slot, the gas port location is still very critical but this would really really help extraction and hence reliability.
The philosophy I subscribe to is run the longest gas system you can in DI.
If that's Midlength because you have a 14.5''+ barrel, if that's a Rifle Length at 18''+, Carbine length at 14.5''or less. (And honestly, alot of people are having great results with running Mid-Length gas systems on 14.5'' so I might just run a carbine length on barrel lengths shorter than 14.5'')
I mean, faster gas port erosion, faster parts wear at higher pressures and more are the concerns.
But again, I haven't seen those documented. They would seem to be true, but I haven't seen it tested either.
What you do know is that it gives more dwell time and less recoil for 2'' of gas tube, a longer handguard, (which IMHO is better for handling the weapon, and even if you don't handle way out there, it's nice to have options, you can attach a bipod, etc.), and usually has a lot less extractor issues as it isn't as "violent" extraction.
Use what you want, but I don't see a downside with going with the longest gas system available as a general rule of thumb.
The only 5.56 bolts I have broken were in carbine gas rifles, one was a Y/M chrome bolt that may have only lasted 1000 rounds the others lasted 4-5000 and they all broke at the cam pin hole. The DOD contractor produced bolts last much longer than the commercial grade bolts. After checking the hardness I do not believe the commercial bolts were Carpenter alloy #158(P6) or were hardened to mil spec. the bolts tested in the low 50s.
Off on a small tangent it appears most chrome carriers are deco chrome(like a car bumper) not hard chrome like the bore inside of a mil spec carrier.