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Posted: 12/17/2005 5:27:16 AM EDT
Normal AR15 rifle (no SBR)

USGI = 20 inches
Legal = 16 inches
Midlength = 18 inches?

Sight radius?

USGI
Legal
Midlength = Dissipator?

Is this something that the well derssed ARFcommer needs?

Link Posted: 12/17/2005 5:35:38 AM EDT

Originally Posted By KA3B:
Normal AR15 rifle (no SBR)

USGI = 20 inches
Legal = 16 inches
Midlength = 18 inches?

Sight radius?

USGI
Legal
Midlength = Dissipator?

Is this something that the well derssed ARFcommer needs?




You are confusing some issues. Midlength is more of a matter of the gas system. If you see the handgaurds, are longer than carbines, but less than a rifle. Most midlengths have a 16" barrel. Not an 18". Also USGI would include the rifle gas system, commonly seen with a 20" barrel and an M4 14.5" barrel with the carbine gas system. Among other things that uncle sam is using.

A dissipator is a weird bird. It uses the rifles handgaurds, but uses a carbine length system. Something about if it used the rifle gas system, it would be too close to the muzzle and not have enough pressure going back through the tube to cycle the action reliably.

This is what I understand. If I am not correct, someone will be along to correct me soon. But I think I've got it right.
Link Posted: 12/17/2005 6:03:46 AM EDT
A midlength is a carbine barrel with a gasblock in a position between the standard carbine and rifle gas block locations. This is for increased reliabilty.
Link Posted: 12/17/2005 6:14:13 AM EDT

Originally Posted By M4Madness:
A midlength is a carbine barrel with a gasblock in a position between the standard carbine and rifle gas block locations. This is for increased reliabilty.



So a midlength rifle barrel is 16 inches long and the gas block is located between where the normal 16 inch sight radius gas block/front tower is located and where the 20 inch sight radius gas block/ front sight tower is located.

So they use different length front hand grips?

Who makes these?

Any pictures?
Link Posted: 12/17/2005 6:25:34 AM EDT
[Last Edit: 12/17/2005 6:47:00 AM EDT by Gunzilla]
Gas port location (approx):

Carbine - 7.5"
Midlength - 9.5"
Rifle - 13.0"

Carbine gas sytems result in reliability and service life proplems... to midlength system is the best solution to the problem. Carbines have excessive pressure at the gas port and the timing is off.

A 16" middy is a sweet shooting litttle gun and (imho) about the only answer for a carbine.
Link Posted: 12/17/2005 6:46:52 AM EDT
[Last Edit: 12/17/2005 7:08:37 AM EDT by BerlinVet]
Contact CCMG...
Link Posted: 12/17/2005 6:53:31 AM EDT

Originally Posted By BerlinVet:
From CCMG Inc,
<snip>



Pictures meaning pictures of a mid length barrel and a carbine length barrel that show the positions of the gas block respective of each other.

I have seen plenty of pictures of uppers with hand guards on them.
Link Posted: 12/17/2005 6:55:28 AM EDT

Originally Posted By Gunzilla:
Gas port location (approx):

Carbine - 7.5"
Midlength - 9.5"
Rifle - 13.0"

Carbine gas sytems result in reliability and service life proplems... to midlength system is the best solution to the problem. Carbines have excessive pressure at the gas port and the timing is off.

A 16" middy is a sweet shooting litttle gun and (imho) about the only answer for a carbine.




So then the question is what's a "carbine" length barrel?

I have nothing but 16 inch barrels from Oly, Clot and Bushmaster and none are "midlength" and they all work fine.

Is this a "machine gun" thing or is it a "military" thing?
Link Posted: 12/17/2005 7:03:27 AM EDT

Originally Posted By KA3B:

Originally Posted By Gunzilla:
Gas port location (approx):

Carbine - 7.5"
Midlength - 9.5"
Rifle - 13.0"

Carbine gas sytems result in reliability and service life proplems... to midlength system is the best solution to the problem. Carbines have excessive pressure at the gas port and the timing is off.

A 16" middy is a sweet shooting litttle gun and (imho) about the only answer for a carbine.




So then the question is what's a "carbine" length barrel?

I have nothing but 16 inch barrels from Oly, Clot and Bushmaster and none are "midlength" and they all work fine.

Is this a "machine gun" thing or is it a "military" thing?



Generally when we talk of "carbine, midlength, ..." it is reference to the gas port location, the three listed the most common (but not the only ones). The barrel length can be anything, but dwell timing gets out of whach if the amount of barrel past the gas port is not someplace close to 6-7 inches (this depends some on the size of the gas port and thickness of the barrel of course.

The issues with a 16" carbine length system are there... mostly noticed during full auto fire; but trust me, if you get your hands on a 16" midlength to shoot, you will notice a difference in the feel of it...

The internal bolt pressure of the midlength drop a few hundred psi from the carbine length system and the reduced bolt velocity is noticable... in full auto fire, the middy really shines!
Link Posted: 12/17/2005 7:14:24 AM EDT
Thanks Gunzilla!
Link Posted: 12/17/2005 7:31:36 AM EDT
[Last Edit: 12/18/2005 8:11:34 AM EDT by stangleonthedangle]
Heres my middy. I love it. And the bayonet fits nicely.


Sorry if the images are huge. I didn't have time to resize them.






Link Posted: 12/17/2005 8:59:37 AM EDT
Hey dude, I have the exact same 1911... Spiffy aren't they

Congrats on your toys.
Link Posted: 12/17/2005 10:52:05 AM EDT
[Last Edit: 12/17/2005 10:52:28 AM EDT by KA3B]

Originally Posted By stangleonthedangle:
Heres my middy. I love it. Ant the bayonet fits nicely.
Sorry if the images are huge. I didn't have time to resize them.
tinypic.com/ip5amu.jpg
tinypic.com/ip5avo.jpg



They do me no good, I can look at AR15's that have hand guards on their barrels all day long on the internet.

I want to see a picture of a 16 inch barrel with "midlength" and "non-midlength" barrrels together, no hand guards.
Link Posted: 12/17/2005 12:25:37 PM EDT
[Last Edit: 12/17/2005 12:26:47 PM EDT by Not_A_Llama]
16,000 posts, and never figured out what a midlength was.

Suddenly deej86 looks like a regular smglee
Link Posted: 12/17/2005 12:28:03 PM EDT
No one NEEDS a midlength - I just prefer them as a carbine setup.

Link Posted: 12/17/2005 12:42:03 PM EDT

Originally Posted By Gunzilla:
Gas port location (approx):

Carbine - 7.5"
Midlength - 9.5"
Rifle - 13.0"

Carbine gas sytems result in reliability and service life proplems... to midlength system is the best solution to the problem. Carbines have excessive pressure at the gas port and the timing is off.

A 16" middy is a sweet shooting litttle gun and (imho) about the only answer for a carbine.



Look, I've heard this and read this before, but how real is the unreliability?? With all the M4's in service and all the carbines that people own on this site alone, I haven't heard people whine about their carbines not running that well. Shoot, look at these guys with the 10.5 and 11 some odd inch barrels. They aint running them on midlength. You kind of make it seem like they've been hamstrung from the beginning. I'm not saying this to be a jerk, I'm only wanting to know the real deal because I'm getting ready to get another upper and am leaning towards a carbine. And it would be my main HD weapon once I get it up and running. It seems like people state the problems, which they actually make sense, but nobody has the problems associated with it.

Help a brother out and lets hear from some carbine length owners about reliability, pretty please!!!!!!!!!
Link Posted: 12/17/2005 1:01:18 PM EDT
[Last Edit: 12/17/2005 1:24:05 PM EDT by Gunzilla]

Originally Posted By JJREA:

Originally Posted By Gunzilla:
Gas port location (approx):

Carbine - 7.5"
Midlength - 9.5"
Rifle - 13.0"

Carbine gas sytems result in reliability and service life proplems... to midlength system is the best solution to the problem. Carbines have excessive pressure at the gas port and the timing is off.

A 16" middy is a sweet shooting litttle gun and (imho) about the only answer for a carbine.



Look, I've heard this and read this before, but how real is the unreliability?? With all the M4's in service and all the carbines that people own on this site alone, I haven't heard people whine about their carbines not running that well. Shoot, look at these guys with the 10.5 and 11 some odd inch barrels. They aint running them on midlength. You kind of make it seem like they've been hamstrung from the beginning. I'm not saying this to be a jerk, I'm only wanting to know the real deal because I'm getting ready to get another upper and am leaning towards a carbine. And it would be my main HD weapon once I get it up and running. It seems like people state the problems, which they actually make sense, but nobody has the problems associated with it.

Help a brother out and lets hear from some carbine length owners about reliability, pretty please!!!!!!!!!



Literally volumes have been written about this subject, the hows and whys are well covered.

So, the carbine length system is not so bad that it does not work... not at all; it is just that there is a better solution out there in the form of the midlength. Mearly all of the problems with high bolt pressure/velocity and FTE/FTF problems can be linked to the fact the gas system on the carbine is not *tuned* as well as it could be...

There are several considerations with the rifle: the available pressure at the gas port, the restriction of the port, the "time" location of the gas port, the dwell of the high pressure cycle... many things come into play, but the fact is that the carbine starts the unlocking process too early and the internal pressures in the bolt are too high -- heavy buffers, and fancy doo-dad gas tubes are a band-aid fix that treats the symptom, not the problem.

Yes, Uncle Sugar knows about it... and it is not being ignored. Those that have used the M4Ward that we put out a couple of years ago are *very* happy with the inprovements it offers (basically a midlength M4) and the Enhanced Battle Receiver (EBR) shows even more improvements...

So, all I can tell you is if you have a carbine length, there is no reason to run out and replace it... but if you are in the market for something new, why not get the system that is proven to be better?

eta: if you are a member of NDIA, you should be able to get more info through there... Ooops, just read where you are from, silly to even ask this!

Our website is being redone for the new year, but the catalog there has a full section on the issues of the gas system and real world results of some of the fixes.
Link Posted: 12/17/2005 2:00:32 PM EDT
16" midlength



16" carbine
Link Posted: 12/17/2005 6:39:46 PM EDT

Originally Posted By Not_A_Llama:
16,000 posts, and never figured out what a midlength was.

Suddenly deej86 looks like a regular smglee





Honestly, I never paid attention to the "midlength fix" for AR15's.
None of my 16 inch "carbines" with the "7.5 inch gas port location" have EVER given me any problems.

I was reading about them this morning so I thought I would ask you guys for info.
Everyone has to learn at some point in time.

Now that I know the whats and whys of the midlength AR15 barrel I can rest easy knowing that I don't need to throw out all of my carbine "7.5 inch gas port location" barrels.

The next AR15 I build I might have to try a midlength AR15 barrel to see if it really is the cats ass.

Thanks again for the info!!
Link Posted: 12/17/2005 6:42:17 PM EDT

Originally Posted By 45Ron:
16" midlength

cmmginc.secure-mall.com/shop/images/502.jpg

16" carbine
cmmginc.secure-mall.com/shop/images/500.jpg



[Bette Middler] Did you know that you're my hero [/Bette Middler]

Thanks man!!
Link Posted: 12/17/2005 11:14:50 PM EDT
Carbine:





Midlength:

Link Posted: 12/18/2005 3:51:21 AM EDT

Originally Posted By topgunpilot20:
Carbine:
img.photobucket.com/albums/v509/topgunpilot20/IMG_1045.jpg
Midlength:
img.photobucket.com/albums/v509/topgunpilot20/Guns/midlength01_web.jpg



[sigh]
AGAIN, I can look at pictures of AR15's with handguards on the internet all day long.
WHAT I ASKED FOR was a set of pictures of the BARRELS, and 45Ron came through.


Link Posted: 12/18/2005 3:53:15 AM EDT
Bayo will also fit a midlength.
Link Posted: 12/18/2005 6:13:31 AM EDT
Does Bushmaster make a mid lenght
Link Posted: 12/18/2005 6:19:43 AM EDT
The midlength's look a lot nicer. It has a better balance between sight radius and HG length.

The 16" carbines have too much barrel sticking out past the front sight, sort of like a 24" H-bar config.
Link Posted: 12/18/2005 7:35:42 AM EDT

Does Bushmaster make a mid lenght

No

I think RRA and ArmaLite are the main middy makers unless you are putting together your own.
Link Posted: 12/18/2005 8:20:55 AM EDT

Originally Posted By KA3B:

Originally Posted By Not_A_Llama:
16,000 posts, and never figured out what a midlength was.

Suddenly deej86 looks like a regular smglee





Honestly, I never paid attention to the "midlength fix" for AR15's.
None of my 16 inch "carbines" with the "7.5 inch gas port location" have EVER given me any problems.

I was reading about them this morning so I thought I would ask you guys for info.
Everyone has to learn at some point in time.

Now that I know the whats and whys of the midlength AR15 barrel I can rest easy knowing that I don't need to throw out all of my carbine "7.5 inch gas port location" barrels.

The next AR15 I build I might have to try a midlength AR15 barrel to see if it really is the cats ass.

Thanks again for the info!!



In my family, we have a rifle, a middy and no carbine. I think I have to get one. Isn't it mandatory now? JK. I understand why there might be problems or people may have problems, but it just seems like it's more theory than real life. I could be wrong though. Believe me, I'm no expert so I'm not trying to take away from what gunzilla said. I just don't know if I buy into it as much. But again, I could be wrong.
Link Posted: 12/18/2005 8:30:33 AM EDT

Originally Posted By JJREA:

Originally Posted By KA3B:

Originally Posted By Not_A_Llama:
16,000 posts, and never figured out what a midlength was.

Suddenly deej86 looks like a regular smglee





Honestly, I never paid attention to the "midlength fix" for AR15's.
None of my 16 inch "carbines" with the "7.5 inch gas port location" have EVER given me any problems.

I was reading about them this morning so I thought I would ask you guys for info.
Everyone has to learn at some point in time.

Now that I know the whats and whys of the midlength AR15 barrel I can rest easy knowing that I don't need to throw out all of my carbine "7.5 inch gas port location" barrels.

The next AR15 I build I might have to try a midlength AR15 barrel to see if it really is the cats ass.

Thanks again for the info!!



In my family, we have a rifle, a middy and no carbine. I think I have to get one. Isn't it mandatory now? JK. I understand why there might be problems or people may have problems, but it just seems like it's more theory than real life. I could be wrong though. Believe me, I'm no expert so I'm not trying to take away from what gunzilla said. I just don't know if I buy into it as much. But again, I could be wrong.



If you think of all the money that people have spent to develope heavy buffers, super springs, enhaced carriers, fat gas tubes, coiled gas tubes, modified extractors, extractor buffers, dual spring setups, expansion chambers, etc, etc...

it seems a lot of time and money for a theory

the problem is real, not as bad as some would have you believe, but still real
Link Posted: 12/18/2005 8:59:55 AM EDT
i like them simply because the bayo fits . no adapter needed..


cant do any drive by bayo charges and looking like a fool with an adapter to make the bayo fit on the end of a 16 in carbine..


never been an issue of them "working better" hell ive never had an issue with the carbine full length or the middy ..

it simply works with the bayo and that why i have mine..
Link Posted: 12/18/2005 9:14:13 AM EDT
Not an endorsement of their products, just an image to demonstrate carbine, midlength and rifle gas system lengths.

Link Posted: 12/18/2005 9:22:14 AM EDT
i have shot my midlength and my carbine...switching off from one to the other and I can honestly saythe recoil of the carbine is brutal by comparison to the middy. The middy shoots very soft and I believe I shoot better with it because of this.
Link Posted: 12/18/2005 9:27:05 AM EDT
Middys just look cool...

Link Posted: 12/18/2005 10:24:14 AM EDT

After reading this thread it would appear that between the longer sight radius (potential for better accuracy) and less recoil/pressure/wear on gas operating system the carbine system has no positives and only negatives. Why are they even still made? Is the new SEBR the carbine style? If so why have Bushy and the other Manufacturers not implemented the mid-length idea and canned the inferior carbine style? If the answer is, "Not yet", OK. If the answer is, "They won't", Why not?
Link Posted: 12/18/2005 11:16:38 AM EDT

Originally Posted By oulufinn:
After reading this thread it would appear that between the longer sight radius (potential for better accuracy) and less recoil/pressure/wear on gas operating system the carbine system has no positives and only negatives. Why are they even still made? Is the new SEBR the carbine style? If so why have Bushy and the other Manufacturers not implemented the mid-length idea and canned the inferior carbine style? If the answer is, "Not yet", OK. If the answer is, "They won't", Why not?



Because the military uses M4s and people would rather imitate G.I. Joe than have a superior rifle.
Link Posted: 12/18/2005 2:11:24 PM EDT

Originally Posted By dsg2003gt:
i have shot my midlength and my carbine...switching off from one to the other and I can honestly saythe recoil of the carbine is brutal by comparison to the middy. The middy shoots very soft and I believe I shoot better with it because of this.



Brutal in comparison???
Link Posted: 12/18/2005 2:42:11 PM EDT

Originally Posted By 0100010:
Not an endorsement of their products, just an image to demonstrate carbine, midlength and rifle gas system lengths.

www.rockriverarms.com/images/bblcm.gif



Thanks!!!
Link Posted: 12/18/2005 3:10:27 PM EDT

Originally Posted By JJREA:

Originally Posted By dsg2003gt:
i have shot my midlength and my carbine...switching off from one to the other and I can honestly saythe recoil of the carbine is brutal by comparison to the middy. The middy shoots very soft and I believe I shoot better with it because of this.



Brutal in comparison???



i was just trying to get my point across, but there is a considerable difference.
Link Posted: 12/18/2005 5:17:40 PM EDT

Originally Posted By JJREA:

Look, I've heard this and read this before, but how real is the unreliability?? With all the M4's in service and all the carbines that people own on this site alone, I haven't heard people whine about their carbines not running that well.



Just look at all the threads mentioning heavy duty extractor springs, heavy buffers, fatboy gas tubes, heavy duty magazine springs, improved bolts, etc. All of these things were designed to address problems that popped up due to the gas pressure and timing issues, Gunzilla mentioned.

You have to understand - nobody is saying the carbine is unreliable or that it sucks. I've seen carbine gas systems with 10k rounds and no stoppages that cannot be traced to mags or ammo. All people are saying is that because the midlength has better timing and gas pressure by comparison, it will put less stress on the internal components. Because the cyclic rate is lower, magazines have more time to position rounds, which gives a shade more reliability.

It isn't that the midlength is overwhelmingly better. It is just that the midlength offers several positives and no negatives. You get a smoother recoil impulse, two inches more sight radius, better long term odds on both durability and reliability and it doesn't cost any more in terms of money or weight compared to a carbine.
Link Posted: 12/18/2005 6:05:43 PM EDT
[Last Edit: 12/18/2005 6:07:56 PM EDT by hkusp]

Originally Posted By 0100010:
Not an endorsement of their products, just an image to demonstrate carbine, midlength and rifle gas system lengths.

www.rockriverarms.com/images/bblcm.gif



I currently have a 20" upper and a 16" CAR upper. My next upper will be a 16" Dissipator. I basically use my 16" upper as dedicated for .22 LR.

Link Posted: 12/18/2005 6:34:45 PM EDT

Crap! Now another upper for the SEBR is swimmin' in my gourd! Can't the pressure just be regulated by different restrictions in the gas system? I realize the carbines are not terrible just maybe not OPTIMAL & I would think a tool tasked with the possibility of defending ones life would be best if it were OPTIMAL? Relative newb here so please be patient as this sinks in.
Link Posted: 12/18/2005 7:04:58 PM EDT

Originally Posted By oulufinn:
Can't the pressure just be regulated by different restrictions in the gas system?



A couple different companies make adjustable gas blocks. I'm not sure that I could install one on a barrel. If you shoot with a suppressor, then an AGB makes more sense since there is a lot more gas coming out of the ejection port. You could then partially shut the gas system down making sure that the bolt still continues to cycle and eject your empty case.

JP Adjustable Gas Block
Link Posted: 12/18/2005 7:19:25 PM EDT
Thanks for the link hkusp. No suppressor or full auto for me but I'll keep the JP in mind if I get another upper. The SEBR will stay as-is to keep it original but a new upper would get either an AGB or a true mid-length system. Thanks again.
Link Posted: 12/18/2005 8:07:54 PM EDT

Originally Posted By oulufinn:
Crap! Now another upper for the SEBR is swimmin' in my gourd! Can't the pressure just be regulated by different restrictions in the gas system? I realize the carbines are not terrible just maybe not OPTIMAL & I would think a tool tasked with the possibility of defending ones life would be best if it were OPTIMAL? Relative newb here so please be patient as this sinks in.



The problem is the location of the port in relation to "time" and the dwell period of the pressure delivery... one starts too early and the other last too long. Smaller ports and regulated gas blocks do not work so well, the solution is to delay the operating pressure in the bolt until later in the firing sequence -- Again, all the doo-dads and stuff address the symptom: Using trick gas tubes, expansion chambers, regulators, heavey buffers, etc, are all band-aids for the port being in the wrong location.
Link Posted: 12/18/2005 8:13:30 PM EDT
I purchased a Dissy because I knew I was legally limited to 16" and I wanted the full-length sight radius. I would have bought a Bushmaster mid-length but DPMS beat them on the price ($700 v. $950).

I haven't noticed any gas problems, my gun is still being broken it (not quite to 500 rounds yet) but no problems so far.
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