Home Forums Hunting & Shooting AR and Tactical Rifles Mil-Spec and Midlength Gas Systems

Can someone explain the good, bad or indifferent of Ar's that are Mil-Spec and also the advantage of a Midlength Gas system over a carbine length system? I am looking at some upper end AR's and see these terms much more common than in a lower end AR.

I think the mid-length gas system is the way to go. An M4 14.5in barrel is quite reliable but less so than the older 20in guns (A1's anyway, IME) TWR will be along to quote gas port pressures but basically the bolt/carrier doesn't get slammed at hard with the mid-length.

Mil-spec is just that, certain grades of steel etc. Some of it doesn't even apply to most civilian usage. Gonna jump out of an airplane or do full auto mag dumps with it?

A friend has used nothing but DPMS stuff/parts for years as a sponsored shooter, he has zero complaints with any of it, but he always shoot somebody else's barrel, 'cause that's what really matters with an AR as far as accuracy is concerned.

No plane jumping for me - scared of heights and bad knees to boot! Mid length and 16" barrel is where my inclination was leaning in an upper end manufactured AR.

Mid length is the latest craze. It is supposed to put less strain on the bolt parts because of less pressure. The average person would never know the difference. Carbines will run a long time if taken care of, same as a midlength. Heavy buffer spring and buffer can slow things down a bit and pretty much accomplish the same thing from what I've read.

Mil-spec is basically got to do with standardization of parts. If the parts or gun is "mil-Spec" you can swap everyones parts back and forth and have a reliable gun. Most AR-15s are Mil-spec.

I was gonna stay out of this but...

First off there is no mil spec AR-15, mil spec is what the govt specs out as what they need, it's my understanding that the TDP (or Technical Data Package) gives all the particulars and as of just last year it belonged to Colt for the M4 and FN for the M16, now it belongs to the DOD. The Colt 6920 is built in the same plant with all the same parts as a mil spec M4 excluding the 16" barrel and full auto. Other companies like Daniel Defense and BCM build as close to the TDP as they can and are called mil spec just like the Colt.

Bushmaster, dpms, Rock River, Delton, Model 1 sales, and plenty of others claim to use mil spec parts but they do not and are not mil spec guns. They take shortcuts that may mean something to you or may not.

Barrel steel, bolt HP and MP testing, extractor springs and extractors, staking, receiver extensions, stocks, type of aluminum, anodizing, etc... all these things have a standard which the TDP lays out to make a mil spec weapon be as reliable and robust as it can be with the past 40 years trial by fire to back it all up.

There are companies that go above and beyond by adding a better SS barrel for more accuracy, other coatings might be as good as or better as well as bolts but they are not what the govt wants. So in short mil spec is a term used way too much and really means nothing to us as hunters/plinkers/shooters.

I like quality guns be it autos or bolts so I stay away from bargain priced guns, they're cheaper for a reason.

I'll add more when I get home...

Thanks for the input guys. I have been looking at Colt and Daniel Defense both and they use the term Mil-Spec generously. I agree with you TWR that with quality comes price and I am just fine with that as long as it is warranted. I like the idea of having superior product, inspection, metallurgy, etc. in any gun even if that means my wallet taking a bigger hit. What's your take on the mid length gas system? I know zilch about this new design and if it is hype, better or no different.

I like the mid length gas, going from memory, it runs about 5000 psi lower than a carbine gas. But it is not a deal breaker for me. I have carbine, mid and an intermediate, setup right they all work.

I don't see one gun doing it all so I have work guns and accurate guns but all of them have quality parts throughout.

none of the ar15's parts that are being sold to the puplic are really mil-spec,its a joke. if they went thru what the real mil-spec stuff does they couldn't sell it as cheap as they are.

Whats' the difference in the Colt sold to the military and what you buy from you gunstore apart from the select fire?

I have a colt LE marked carbine, wonder if they take shortcuts. I bet probably not.

That's why Colt parts ain't cheap, they do meet mil spec. Again, mil spec doesn't mean it's the best for all situations, that's the only joke.

A 16" barrel, roll markings, the web in the lower preventing a DIAS and the new Rogers stock. The new production Colts even have gone back to standard sized pins.

thats what I thought...."mil-spec" just doesnt have the aura-factor for me anymore

Now just being "mil spec" doesn't make it the best for every use. As a friend of mine reminds me of, it also can mean "low bid".

But let's say you want a coyote calling carbine. Start with a Colt 6920 and the first thing I'd change would be the barrel and forearm. I'd want a SS match grade barrel and I'd want it free floated. I'd also like to change the stock to a SOPMOD and a 2 stage trigger. The rest of the parts are good to go.

Now if I wanted a duty weapon, the 6920 or my favorite the 6720 (light weight barrel) would serve admirably as is. The chrome lined barrel serves this role perfectly and of course the rest of the gun is built right.

Step down to a, oh let's use dpms for an example, the internal parts can be hit or miss from what I've seen, I don't trust them so I'd change out every part in the lower for sure. The receiver extension is commercial and won't take the SOPMOD stock so it'd have to go but don't worry, the castle nut isn't staked so it'll come loose without a problem. (if it were RR, you'd better get out the torch, they use red loctite) I'd restake the gas key after retorquing the screws and change out the extractor spring and the extractor too. Add a good barrel and you'd have lipstick on a pig so to speak.

Now for a range gun or plinker, I'm sure these other guns would do fine. But I want more, I don't even look at the Remington 710's or whatever their bargain model is now and I don't hear anyone comparing them to the 700's as being just as good as, why is that?

Does that mean all others are junk? Not hardly. It's just the more corners cut, the odds of getting a lemon go up...

Sorry but that's been my experience.

As to mid vs carbine, the carbine is said to tap 26k psi at the port, the mid taps 17k, rifle gas is 13.5k. Both work but the carbine is or can be rougher on parts. Given the right sized gas port (one designed to run with NATO pressured ammo) and a buffer to match, it runs well. The mid length is a smoother ride but most would be hard pressed to tell which one they were shooting if they both were set up right.

Who makes your favorite LPK"s

I have been buying Armalite. To each his own I guess. You also get about 1.5 extra inches of sight radius with the mid length gas blocks over the shorter M-4. I understand a lot of Armaite stuff is going somewhere and finding it has been difficult recently. kwg

http://www.gandrtactical.com/cgi-bin/commerce.cgi?preadd=action&key=CLPK

but I don't have any problems using Rock River LPK's either especially with the 2 stage trigger. I do replace the disconnector brad with a longer pin which is said to be their weak link.

http://www.joeboboutfitters.com/RRA_Two_Stage_Match_Trigger_Kit_AR0093NMK_p/rra-ar0093nmk.htm

Armalite has always been hard to find from time to time. I know of no govt contracts though.