I am in the process of planning a build and was thinking I'd like to keep the length as short as possible while staying within the limits of the law. 

 

Currently i'mn exploring two barrel options:

Option 1 - 14.5" barrel with pinned brake

Option 2 - 12.5" barrel with 4.5" compensator, pinned

 

So my question is, will I be sacrificing accuracy/velocity/reliablity etc. by using a longer compensator with a shorter barrel?

 

So my question is, will I be sacrificing accuracy/velocity/reliablity etc. by using a longer compensator with a shorter barrel?

Yes

perfect, all i wanted to know..thanks

IMO it would defeat the purpose of getting the short barrel since you have to bring it to 16"

What distance you plan on shooting? Sub 150 yards you maybe ok. You probably wont see much of weight loss though with the 4.5" comp.

 it would be for shorter range. the 12.5 with comp was for asthetic purposes. I built a model on gunstruction with 11+" FF rail that just looked awesome. But if it grossly affects performance id bag it.

I wouldnt sweat the performance if your planning short range

25-100 yard range most often

You will not lose accuracy. There is a possibility you have increased accuracy. But you have reduced velocity quite a bit so there will be holdover chiming in very quickly every hundred yards past the first couple. If that matters.

 

M193 could be less effective in a fight because it is less likely to fragment, especially after 25 or 50 yards, but up-close, too. So, it would provide a slight advantage to use heavy OTMs even for close range.

 

It's going to be a lot louder. Great on the range for fun, mixed bag in a fight.

 

Best bet is it will be less reliable. These barrel lengths are not the way the M16 was designed. You gun will have to rip the spent casing out of the chamber via the extractor. Definitely add boosted extraction, like Defender or O-rings and other stuff. SEALS use 10.5" barrels, but their shit is custom. People have used short barrels on ARs for 50 years. But it wasn't designed to work that way, so don't complain unless you have the real stuff.

 

I don't know all the crazy breaks and comps you guys use, but when somebody says 4 inches, I get scared about "moderators" (silencers according to ATF). I'm probably unnecessarily complicating it, but give it a quick check.

You will not lose accuracy. There is a possibility you have increased accuracy. But you have reduced velocity quite a bit so there will be holdover chiming in very quickly every hundred yards past the first couple. If that matters.

 

M193 could be less effective in a fight because it is less likely to fragment, especially after 25 or 50 yards, but up-close, too. So, it would provide a slight advantage to use heavy OTMs even for close range.

 

It's going to be a lot louder. Great on the range for fun, mixed bag in a fight.

 

Best bet is it will be less reliable. These barrel lengths are not the way the M16 was designed. You gun will have to rip the spent casing out of the chamber via the extractor. Definitely add boosted extraction, like Defender or O-rings and other stuff. SEALS use 10.5" barrels, but their shit is custom. People have used short barrels on ARs for 50 years. But it wasn't designed to work that way, so don't complain unless you have the real stuff.

 

I don't know all the crazy breaks and comps you guys use, but when somebody says 4 inches, I get scared about "moderators" (silencers according to ATF). I'm probably unnecessarily complicating it, but give it a quick check.

 

invaluable info thank you. I understand what your getting at in terms of design. I could add the stronger extractor spring similar to my 7.62x39, solved all extraction issues.

 

questions.....

Defender?

OTM's?

holdover?

 

here is the comp/brake im talking about. Im trying to see if this seller has a website or there is a company that produces this. if there is they may have a disclaimer a little more solid then an ebay description stating this is not a silencer

 

http://www.ebay.com/itm/331042813965?var=540253031416&ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1438.l2649

 

This will be something i'll have to think about for a bit. Obviously performance trumps asthetitcs, but as I said this would look pretty savage almost like an SBR where the FF rail ends an inch or so before the comp starts. 

.....a range toy if you will...

 

EDIT: found the site http://us-socom.com/

for what its worth I have a 7in AR15 that I shoot on the regular out to 50 and it runs fine.. I know that pumpkins are just pumpkins.. but rounds were pencil hole in and softball hole out.... I do agree that the velocity is likely way low.. and out at like 100 it would probably be an issue.. but the gun was not put together for distance.. 

thanks for the input...Ill probably go for it unless anyone else can point out some red flags.  I'll probably have the pin and weld done locally by a professional.

invaluable info thank you. I understand what your getting at in terms of design. I could add the stronger extractor spring similar to my 7.62x39, solved all extraction issues.

 

questions.....

Defender?

OTM's?

holdover?

 

here is the comp/brake im talking about. Im trying to see if this seller has a website or there is a company that produces this. if there is they may have a disclaimer a little more solid then an ebay description stating this is not a silencer

 

http://www.ebay.com/itm/331042813965?var=540253031416&ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1438.l2649

 

This will be something i'll have to think about for a bit. Obviously performance trumps asthetitcs, but as I said this would look pretty savage almost like an SBR where the FF rail ends an inch or so before the comp starts. 

.....a range toy if you will...

 

EDIT: found the site http://us-socom.com/

 

have you researched that product? found quality feedback on it?

I have not heard of them before.. 

been looking around and havent seen any  reviews yet. It would not be entirely necessary for me to use that company and i would consider other comps that created the same visual affect

 

 

would anyone care to make a recommendation?

I regularly shoot a 11.5" Colt R0933 'Commando' as that is what I am issued at work. I am also the Agency armorer and am responsible to keep our Colt R0933s running. I use a standard BCG with standard extractor, replacing them often, and after many thousands of rounds have had exactly zero issues with it. It does run harder, and PM schedules are compressed because of it, but as long as you keep on top of it, you should have no issues. That being said....

 

The ONLY reason for having a short barrel is to have a shorter barrel, essentially making the gun "handier" in CQB/FISHing/VBSS or other tight spaces and to cut some weight. Everything else about a short barrel is a negative - Inferior terminal ballistics, premature wear on the barrel (I have been through 2 in 4 years due to extreme gas port erosion), less reliable gas system, and if you shoot a lot like I do, increased PM rates (plan on replacing your action spring, BCG, Gas Tube, and muzzle device at accelerated intervals). I also wouldn't shoot anything lighter than 62gr for best results in it, and don't expect stellar terminal ballistics past 75 yards even with 75gr OTM rounds.

 

Personally, a 12" barrel with a 4" comp makes absolutely no sense to me. You arehoping to havealan of the negatives of a SBR while enjoying zero of the positive attributes. Why you would not use every required inch to improve the terminal ballistics of the rounIFAK beyond me. We use SBRs at work for a specific reason and in that niche role it works. If I had a choice, or the ability to have my cake and eat it too in this instance, I wouldn't carry a rifle with less than a 14.5" barrel.

 

 

Mipafox, where are you getting your short barrel = increased precision data from? That is counter to my experience. All thing being equal performance from 0-150 yards was almost identical on a 11.5" vs a 14.4/16" gun. After 150 yards the accuracy of the SBR suffered greatly.

I regularly shoot a 11.5" Colt R0933 'Commando' as that is what I am issued at work. I am also the Agency armorer and am responsible to keep our Colt R0933s running. I use a standard BCG with standard extractor, replacing them often, and after many thousands of rounds have had exactly zero issues with it. It does run harder, and PM schedules are compressed because of it, but as long as you keep on top of it, you should have no issues. That being said....

 

The ONLY reason for having a short barrel is to have a shorter barrel, essentially making the gun "handier" in CQB/FISHing/VBSS or other tight spaces and to cut some weight. Everything else about a short barrel is a negative - Inferior terminal ballistics, premature wear on the barrel (I have been through 2 in 4 years due to extreme gas port erosion), less reliable gas system, and if you shoot a lot like I do, increased PM rates (plan on replacing your action spring, BCG, Gas Tube, and muzzle device at accelerated intervals). I also wouldn't shoot anything lighter than 62gr for best results in it, and don't expect stellar terminal ballistics past 75 yards even with 75gr OTM rounds.

 

Personally, a 12" barrel with a 4" comp makes absolutely no sense to me. You arehoping to havealan of the negatives of a SBR while enjoying zero of the positive attributes. Why you would not use every required inch to improve the terminal ballistics of the rounIFAK beyond me. We use SBRs at work for a specific reason and in that niche role it works. If I had a choice, or the ability to have my cake and eat it too in this instance, I wouldn't carry a rifle with less than a 14.5" barrel.

 

 

Mipafox, where are you getting your short barrel = increased precision data from? That is counter to my experience. All thing being equal performance from 0-150 yards was almost identical on a 11.5" vs a 14.4/16" gun. After 150 yards the accuracy of the SBR suffered greatly.

 

 

not all people are like you and me..

 

he lives in a state with restrictive laws.. he is essentially making a toy... a gun to mimic a SBR... 

something learned here is not all people only own guns that function in the most ideal manner possible.. 

Vlad, you have a point in that this would be a novelty piece, and I see what high exposure is saying. As you stated NJ does not allow features that add actual functionality to the weapon because thats evil hahah otherwise i'd love an SBR. I have other AR's that I consider to be my tools to get the job done. This is one of those funky custom two tone deals because I love the possibilities when using this platform. 

 

it seems i'd be sacrificing  waaaayyy to much function while dropping the same amount of money to build. 14.5 is looking like the better option

The more I shoot them, the more I think that a 14.5" midlength is THE answer for a general use carbine.

The more I shoot them, the more I think that a 14.5" midlength is THE answer for a general use carbine.

 

 

my "go to gun" is a 14in mid length.. but in the tight confines of a home I find the 7in far more nimble.. 

I have cleared many structures and run more shoothouses than I can count. I see very minor advantages to the SBR vs the 14.5".

 

For me the SBR shines working in and around vehicles, and that was the mission requirement that led us to them. The ability to remove the rifle from a rack, sling it, and charge it - all without getting out of the car or smashing a window out - is a huge advantage.

 

Most people don't have that requirement, and I get that. But the SBR also has a very high CDI factor.

The more I shoot them, the more I think that a 14.5" midlength is THE answer for a general use carbine.

 

 

I have cleared many structures and run more shoothouses than I can count. I see very minor advantages to the SBR vs the 14.5".

 

For me the SBR shines working in and around vehicles, and that was the mission requirement that led us to them. The ability to remove the rifle from a rack, sling it, and charge it - all without getting out of the car or smashing a window out - is a huge advantage.

 

Most people don't have that requirement, and I get that. But the SBR also has a very high CDI fac

 

 

if you are comparing an 11in gun and a 14in gun then sure.. having handled both of these I agree the difference is minimal at best.. but down to 7in for me at least.. made a pretty big difference.. 

you are talking a gun that has a barrel that is half the length.. 

 

now I have not cleared houses and all this and that.. but I have shot in areas with setup barriers and tight corners and the 7in gun feels like it maneuvers betters.. but i guess to each their own.. lol 

I regularly shoot a 11.5" Colt R0933 'Commando' as that is what I am issued at work. I am also the Agency armorer and am responsible to keep our Colt R0933s running. I use a standard BCG with standard extractor, replacing them often, and after many thousands of rounds have had exactly zero issues with it. It does run harder, and PM schedules are compressed because of it, but as long as you keep on top of it, you should have no issues. That being said....

 

The ONLY reason for having a short barrel is to have a shorter barrel, essentially making the gun "handier" in CQB/FISHing/VBSS or other tight spaces and to cut some weight. Everything else about a short barrel is a negative - Inferior terminal ballistics, premature wear on the barrel (I have been through 2 in 4 years due to extreme gas port erosion), less reliable gas system, and if you shoot a lot like I do, increased PM rates (plan on replacing your action spring, BCG, Gas Tube, and muzzle device at accelerated intervals). I also wouldn't shoot anything lighter than 62gr for best results in it, and don't expect stellar terminal ballistics past 75 yards even with 75gr OTM rounds.

 

Personally, a 12" barrel with a 4" comp makes absolutely no sense to me. You arehoping to havealan of the negatives of a SBR while enjoying zero of the positive attributes. Why you would not use every required inch to improve the terminal ballistics of the rounIFAK beyond me. We use SBRs at work for a specific reason and in that niche role it works. If I had a choice, or the ability to have my cake and eat it too in this instance, I wouldn't carry a rifle with less than a 14.5" barrel.

 

 

Mipafox, where are you getting your short barrel = increased precision data from? That is counter to my experience. All thing being equal performance from 0-150 yards was almost identical on a 11.5" vs a 14.4/16" gun. After 150 yards the accuracy of the SBR suffered greatly.

 

 

Out of curiosity HE, Do run a standard A2 flash hider on the RO933 or do you run a comp/brake?

if you are comparing an 11in gun and a 14in gun then sure.. having handled both of these I agree the difference is minimal at best.. but down to 7in for me at least.. made a pretty big difference..

you are talking a gun that has a barrel that is half the length..

 

now I have not cleared houses and all this and that.. but I have shot in areas with setup barriers and tight corners and the 7in gun feels like it maneuvers betters.. but i guess to each their own.. lol

 

 

After a few years experince with the SBRs following many years use of a standard Colt M4 (14.5" barrel, carbine gas system) I am not completely convinced that the noted deficiencies in the terminal ballistics, increased maintenance cost in both time and money, and the reduced reliability inherent in any SBR platform are worth the savings in length - even a 50% savings in OAL, as the shorter you go the more drastic the deficiencies become - or any perceived increase in "maneuverability" (for lack of a better term) even for a pure CQB/FISHing job description.

 

I have shot 7" guns as well. I am not a fan of them for social work at all, especially in a team setting. Very distracting & painfully loud indoors (an NFDD is less distracting and has subjectively less concussion and over pressure than someone shooting a 5 round string from a 7"-10" barelled AR right next to you indoors), it is much more fatiguing being cramped on that short handguard for extended periods of time, and that ultra short barrel allows body parts and partners to move in front of you at the worst opportunities - Bad ju-ju!

 

I look at those ultra short SBRs the same way I look at folks that attempt to justify the use of a 7yard zero. It is useful in such a limited set of circumstances as to be impractical. And the shorter you go, the more the deficiences are noticable. Looking for a toy? Groovy, ultra short barreled ARs are tons of fun at the range. Looking for a defensive tool to protect your home? Stick to proven TTPs and equipment - with the right ones you can clear a phone booth with a 14.5" barrelled AR with little difficulty.

 

Again, this is my philosophy and experience based on my specific needs and personal requirements. Your rifle, your choice.

 

 

Out of curiosity HE, Do run a standard A2 flash hider on the RO933 or do you run a comp/brake?

The SBRs all have a standard A2. Being issued guns, it is hard to change certain parts without a lot of bellyaching by the Admin.

SBRs excel when a can is put on them.  Even the smallest AAC 5.56 can adds nearly 3" in OAL and that one just takes the edge off.  It's still a wicked loud report indoors.  The M4-2K is probably the way to go if working indoors as it is much more effective however adds 5" to OAL, bringing a 10.5" SBR to about the length of a 16" barrel.  Running an SBR without a can indoors is not fun at all, especially when working with a team as it plays havoc with communication.

man it would be nice to put an actual can on.

 

I regularly shoot a 11.5" Colt R0933 'Commando' as that is what I am issued at work. I am also the Agency armorer and am responsible to keep our Colt R0933s running. I use a standard BCG with standard extractor, replacing them often, and after many thousands of rounds have had exactly zero issues with it. It does run harder, and PM schedules are compressed because of it, but as long as you keep on top of it, you should have no issues. That being said....

 

The ONLY reason for having a short barrel is to have a shorter barrel, essentially making the gun "handier" in CQB/FISHing/VBSS or other tight spaces and to cut some weight. Everything else about a short barrel is a negative - Inferior terminal ballistics, premature wear on the barrel (I have been through 2 in 4 years due to extreme gas port erosion), less reliable gas system, and if you shoot a lot like I do, increased PM rates (plan on replacing your action spring, BCG, Gas Tube, and muzzle device at accelerated intervals). I also wouldn't shoot anything lighter than 62gr for best results in it, and don't expect stellar terminal ballistics past 75 yards even with 75gr OTM rounds.

 

Personally, a 12" barrel with a 4" comp makes absolutely no sense to me. You arehoping to havealan of the negatives of a SBR while enjoying zero of the positive attributes. Why you would not use every required inch to improve the terminal ballistics of the rounIFAK beyond me. We use SBRs at work for a specific reason and in that niche role it works. If I had a choice, or the ability to have my cake and eat it too in this instance, I wouldn't carry a rifle with less than a 14.5" barrel.

 

 

Mipafox, where are you getting your short barrel = increased precision data from? That is counter to my experience. All thing being equal performance from 0-150 yards was almost identical on a 11.5" vs a 14.4/16" gun. After 150 yards the accuracy of the SBR suffered greatly.

 

 

I agree at least 95% of that. Especially gas port (I shoot FA on short junk barrels).

 

Shortening a barrel does not inherently reduce accuracy. It reduces velocity which can cause greater problems with holdover and wind drift (medium/long range), and that can reduce effective accuracy. Accuracy also drops when the bullet hits subsonic transition. So short barrels are probably not good for long range in most cases. However, there is less barrel whip with short barrels. And, especially with respect to basic barrels that have not been tuned based on harmonics or manufactured to match specs. Common short barrels are often more accurate within their intended range if the basics of marksmanship are not compromised by the barrel length.

 

Further, we are whizzing these lil bullets and we all know some of them can be more accurate with certain barrel twists and bullet lengths/weights than others. Even when they are "stable." Well, velocity plays into that on the ends of barrel twist.

 

man it would be nice to put an actual can on.

 

 

You'd be disappointed. It still sounds like a gun with regular old .223 or 5.56. It just sounds like a .22 instead.

   

 

You'd be disappointed. It still sounds like a gun with regular old .223 or 5.56. It just sounds like a .22 instead.

That's what someone said once at range day.  I took the can off my 10.5" SBR and shot it once.  Set off a car alarm in the parking lot.  Everyone was shocked at how much work the can was doing after that.

Sure, but it won't make a 20" barrel much quieter than the 10.5" barrel.

 

10.5" barrels are thunderous, who knew?

 

I use my 5.56 auto rated can exclusively on an 11.5" barrel. When I shoot it without the can, it comes up your heals from the ground and runs up your spine before the sound or shockwave reaches you.

 

But it still sounds like a gun with the can on. My M11/9 does not sound like a gun with the can on. And I can shoot .22 with even my 5.56 can on in the next room while you are sleeping and you won't wake up.

 

5.56 cans are great for work but not great choices of silencers for normal people laying out the cash and waiting 15 months. They want to shoot quiet aned it doesn't do that.