Mid length vs M4 carbine

[kev]

While researching the purchase of a new AR-15, I came across several forum topics on the M4 Carbine VS midlength debate.

It seems that the midlength rifle is a little more reliable then the M4, mainly due to pressures in gas system.

The question I have, in most of the debates people keep using the word "slightly". How much is slightly? Is a midlength 20% more reliable then the M4 gas system, 10% more reliable, 5% more reliable, 2% more reliable, .005% more reliable,,,,?

Surely there has been some kind of government, FBI or military study that shows the difference between the M4 and midlength systems?

The reason I am asking, I am down to the final line on a new AR purchase. At this time I am looking at a Spikes ST-15 midlength, or the M4 version. I like the looks of the M4 version, but I also want a full length 16 inch barrel + flash hider, and not a 14.5 inch barrel + flash hider.

It seems to me that some people try to break the AR15 into a science (correct me if I am wrong). I just want a rifle that works, and is compact enough to carry in my truck, in my boat, or on an ATV.

On the rifle I am hoping to add a Magul MOE grip + surefire tactical light. It seems to me that the M4 version would be easier to operate with everything so compact and close together.

I would like to hear from people who have combat experience with either the midlength of M4 versions. Which version do you prefer and why?

The intended purpose of the rifle is for home / property protection.

This is my Bushmaster Xm15 that was made during the assault rifle ban. I am leaning towards another M4 version so the parts can interchange easier.

[TDFbound]

Anybody with combat experience with either of these will have used the M4 with a 14.5" barrel, since that is what is issued. Either that or a standard 20" M16.

[reverendg]

Both systems function reliably for me, don't have any percentages. The carbine system is a little harsher in function, nothing you couldn't cure with a heavier buffer if need be. The middie system probably saves a little wear and tear on the gun, but I doubt it is any real savings over the usable life of the weapon. I personally prefer the middie system, just personal opinion.

[Kimberuser]

I would go with the collaspable stock. I had one on my M4 in the army and mine never jammed. That way you can adjust the stock into the postion that is most comfortable to you. If you are shooting in tight spaces, then you can collaspe it, or if you like the extended stock you can extend it. I prefer flexibility. For reliability I honestly dont know how it affects.

[Getyershells]

Kev,

You won't go wrong with an ST-15 (if you can find one in stock) There is a long wait period if you buy from Spikes website. They are backordered.

I own an ST-15 Mid-Length carbine. The biggest difference I can tell between a midlength vs a carbine length is the middy has smoother, softer recoil. The middy will be a bit heavier than the carbine length.

As you stated (in theory) the middy has higher longevity due to the length of the gas sytem. Not sure that there has ever been any actual testing to verify this but it makes sense to me. It will run cooler but when you are shooting 100's of rounds it's not really going to matter. Both guns are going to heat up.

[merlinfire]

my m4 has never jammed but then i've not submerged it in mud and !@#%ed in it either.

so can't say what it would do under those circumstances.

however a middy will be slightly heavier, but due to the weight will reduce muzzle rise and perceived recoil

[backwoodsbullets]

I have a 20in on my ar. My next one will either be a 16-18 with the rifle gas system. One like said earlier a little easier recoil and two i want the greater distance for a better sight picture. I had a shorty and didnt like it. I love my rifle but to long for cleari.g the house. So im going with the 16 with full length rails and gas system. As far as reliable i never had problems with the m4 not preforming like it should.

[Icculus]

Originally Posted by merlinfire

however a middy will be slightly heavier, but due to the weight will reduce muzzle rise and perceived recoil

Why because it has 2 inches more of gas tube? Identically configured guns; one carbine gas and one a middy; and there will be virtually no weight difference. Now if they have different things on them (rail, stock, optics) then different story.


OP. I don't have actually figures in front of me but here's a small comparison. One AR is a DD, full 12 in Omega X rail, heavy ass ACS stock, gov't provile 16in barrel with carbine gas system. With optic and loaded mag it comes in at around 9-9 1/2 lbs. Second is a BCM with a 16in pencil barrel with middy gas, moe handguard, ctr stock. It's the lightweight training gun and with optics and mag probably comes it at 7 1/2 lbs. The heavier DD gun should absorb more of the recoil than the light gun but the middy is definitely a softer shooter.

I would say get the middy but if you get the carbine you will be perfectly fine as well (assuming bought from a quality mfg). The only issue I've seen with a middy was a 14.5" middy (with pinned FH to make legal) and it had some problems cycling the horribly underpowered wolf ammo. As long as you aren't shooting the cheapest ammo you can find and sticking with a 16" barrel, I think you will like the middy better. Pair it with a Vltor A5 kit and you're gold.

[lordsuprememaster]

As said above if you wish to stick with the carbine definitely go with the heavier buffer such as the Spikes ST-T2. I recently installed one and bought both the car and spike buffer to the range for a comparison and could tell the difference.

[Getyershells]

[QUOTE=Icculus;3675019]Why because it has 2 inches more of gas tube? Identically configured guns; one carbine gas and one a middy; and there will be virtually no weight difference.[QUOTE]

I wouldn't think the weight difference comes from 2 inches of extra gas tube but from the middy not having the barrel cut out for an M203 attachment.

As far as making a difference in recoil ounces do count. It probably wouldn't make much differnce in what the carrier feels but with muzzle climb.

But as you stated different configurations in furniture, and accesories will make the biggest difference.

[kev]

I am kinda leaning towards a midlength AR-15.

Even though I already have a carbine version, it would be nice to have something different. At least then I can do side-by-side comparisons.

And, I really like the look of the rifle Getyershells posted in this thread - http://www.survivalistboards.com/sho...d.php?t=211263

[MikeK]

For proper function, there has to be a specific length of barrel in front of the gas port. The M4's gas port location was correct for the shorter military barrels. They just kept the same location when the 16 inch carbine length guns started hitting the civilian market. The mid length system slows the cyclic rate somewhat, which decreases the perceived recoil and helps reliability a bit.

What I especially appreciate about it is the increased sight radius. Personally, I think the dissipator concept over a mid length gas system is just about the perfect compromise.

[Rockclimber]

The main concern is bullet velocity. Shorter barrels will cause the bullet to travel slower causing them to not tumble at yards greater than 200-300. After 200-300 yards the round will only be as effective as a .22

[Getyershells]

Originally Posted by Rockclimber

After 200-300 yards the round will only be as effective as a .22

Are you trolling or are you being serious?

[Metcalf]

My current AR was a built by me. I went down to a 14.5" barrel with a mid-length gas system. The muzzle device is pinned and welded in place to keep it legal. I used a low profile gas block and a free floating rifle length handguard. The front sight is on the end of the rifle length handguard for a nice long sight radius and plenty of room to get my hand WAY out for stability.

I love this combo. It shoots everything I feed it. It is more than accurate enough for a non-scoped rifle with iron sights or a red dot.

I HIGHLY suggest building your AR yourself. Its rather easy overall and you will get more rifle for your money.

[Icculus]

Originally Posted by Getyershells

I wouldn't think the weight difference comes from 2 inches of extra gas tube but from the middy not having the barrel cut out for an M203 attachment.

I think we're on the same page but my guess is the weight savings of the M203 cut would be negligible. Yes the middy wouldn't have the cut but as the fsp is pushed out further there is an extra 2" of smaller barrel profile behind gas block. Don't have actual weights but probably evens out.

Now if you go with a lightweight barrel there are some real weight savings. If you look at numbers 27 and 28 the LW saves you 4.8 oz.
http://www.03designgroup.com/technot...ht-comparisons

With the middy you probably get a more appropriate dwell time for a 16" barrel plus the added bonus of a longer sight radius. I won't say there is a single thing wrong with the carbine gas and wouldn't necessarily pay to make the switch if you already had the rifle. But when buying a new one its hard to find a real reason to go with the the shorter gas system.

[arizonafusilier]

Gang, I have read the thread carefully, but I am not familiar with term "middy" in this context.

Is it the barrel length, or the gas tube? And how long is it?

[Icculus]

Originally Posted by arizonafusilier

Gang, I have read the thread carefully, but I am not familiar with term "middy" in this context.

Is it the barrel length, or the gas tube? And how long is it?

Sorry middy=mid-length gas system. Basically a 9.5" gas system vs the 7.5" carbine.

http://m4carbine.net/showthread.php?t=51748

[corndogggy]

I think these debates are all theoretical personally. I mean, I have a BCM 16" mid-length and it was harsh as hell, seemingly overgassed, and would recoil when the buffer hit the back of the tube too fast. I put in a spikes buffer and it calmed down quite a bit, but still, a mid-length gas system shouldn't need such a thing if you listen to what everybody says about them. I consider the Spikes buffer to be a band-aid and didn't like having to resort to that.

In contrast, you can watch the videos on a Daniel Defense M4 with a carbine gas system and they hardly move at all when you pull the trigger. According to the legend it should be the other way around, a heavy mid length should be crazy stable as compared to a light carbine but that doesn't seem to be the case.

In other words, it's all about how well the entire system is tuned. Spring rate, buffer weight, bolt weight, gas tube length, gas tube size, gas tube rear port size, barrel length... there's a whole bunch of things that need to work together.

If I were to do it over I'd get a Daniel Defense carbine system and be done with it. Also supposedly if you got a mid-length, the 14.5" barrels are supposedly actually smoother than the 16" like I got. I'm assuming that's because a 16" has another 1.5" that the bullet has to travel and more gas is pressing into the gas port during this time. A 14.5" should have slightly less gas pressure due to a smaller timeperiod that the gas can enter in other words. Of course this is due to BCM marketing too, but yeah supposedly a 14.5" mid-length is the smoothest shooting thing they offer.

[jaloysiusc]

i have a 20" A2, a 16" CAR (m4 profile), and a 16" midlength. my favorite is the A2. it is the most accurate rifle that i have owned! as for the 2 16" rifles, i think they are pretty much the same. i love all my rifles.i rally dont have any complaints about either one.