I've been playing with the idea of a 11.5" SBR with a SIR rail system. My previous intent was to go with a 14.5".
Vortex on the barrel too.
I want to put together a medium - close range weapon.
My only worry is the balistics from that length of barrel.
I want to top it off with a TA-31 Trijicon ACOG. I do not want to go with a non-magnified scope, such as an Aimpoint.
This seems like it would be one hell of a CQC weapon. Great for in and out of cars. Light weight package with little weight out front. Forward M900 Surefire grip. I've got the Magpul M93 on it already.
With the balistics issue, I'm sure it could be solved by choosing a proper load.
Any thoughts?
-Steve

It is a handy length, put a suppressor on it, it gets a bit long.

I just dragged out the 15 yr old green "CHRONY" yeterday, fired 3131A, SB 93 SS-109 from my Colt 20 1x7, Bushmaster 11.5", and DPMS 7.5"....

Average for 5 shot:

3131A-- 20"---- 3234
*       11.5"-- 2788
*       7.5"--- 2382


SB-93/SS109-- 20"---- 3096
*             11.5"-- 2693
*             7.5"--- 2345

[img]www.imagestation.com/picture/sraid58/p8ebef1b96620f22e9dd71fb010b835fd/fc681adc.jpg[/img]

go with a 1/7 twist if you can find it in such a short barrel. This would remedy some of the SBR ballistics by allowing the use of very heavy bullets.

If you ever have intention of getting a suppressor, see if there are any reflex style suppressors available in the US.  If so get the 14.5  I don't know if BR Toute has the only rights to manufacture this type of design or not.  They are pretty neat suppressors.  I'll give you a link right to a picture of an AR with a reflex can on it.  Maybe a length comparison pic too.

[url]http://guns.connect.fi/rs/Reflex.htm[/url]

[url]http://guns.connect.fi/rs/ar15supp.html[/url]

The reason to get the 14.5 is that you would gain the lethality of a longer barrel/higher velocity, but not really sacrific compactness [b]IF[/b] you could get a reflex style can.

I suppose if you used 75/77 grain bullets, an 11.5 barrel could reach out there a ways, but no one has done any chrony work with them.

Oh, seeing that you wanted a phantom flash suppressor, your overall length with a 4 baffle reflex suppressor would not be much different.  And the can does the same flash hiding job, plus it is a lot quieter.

Civilian ownership of non-US made sound suppressors have not been allowed in the US since 1968.

I've been using a vortex on a 10 & 11.5; both performed great.

This is the exact same set-up I'm thinking about.I'd like to use my Eotech instead though.I had a carbine instructor who is ex-Delta and suggested staying away from the ACOGs for CQB because the Aimpoints and Eotechs pick up targets quicker.But that's just his opinion from personal combat experience.I'd also like to know what barrel twist rate would be best for shooting M193 out of the 11.5" barrel?

I think Hail Mary's point is there are no reflex cans available in the US at this time.  I checked into it and its just not available.  Also there are no quick attach/detatch cans available anywhere.

I think there would be quite a market for such a device and I wish they would make one, here in the US so I can have one of course.  Does anyone know why noone makes a reflex can in the US for civilian consumption or why they dont have quick detatch versions or am I missing a product in my searches for a suppressor?

Reaching out there a ways is a relative thing.
75m-100m is realistic for "social" purposes, with the limitation being terminal effects more than accuracy. That is reaching out there a ways compared to handguns and pistol caliber SBR's. It will have a advantage on anything its size or smaller.

I think the 11.5" barrel is a great idea so long as you realize you cant leave your state and just take the rifle anywhere you want unlike a 14.5" barrel plus vortex.  You should consider a quick attach/detatch unit for the weapon as its going to be very loud without it.  I mean why not since you are going class 3 anyway right?  KAC is lighter and tougher.  Gemtech is quieter and less expensive.

Make sure the barrel is 1/7 twist so you can use 75 or 77 grain ammo and have decent terminal ballistics and reasonable range of fragmentation.  Using 68/96 grain ammo will not give the dramatic results from a 11.5 that it gives in a 14.5 or 16" barrel with a 1/9 twist.  Also make sure your gas port is the correct size.  You will probably end up with a Colt barrel if you are serious about this SBR project.  You could cut down a 14.5" 1/7 twist Bushmaster M4 barrel and open up the gas port but after all the work and waiting you could have just gotten a 1/7 twist Colt for just a bit more money and have it ready to go as soon as you get it.

Now the external ballistics are another issue.  The various reticles of the TA31 dont match the 75 and 77 grain ammo as the 75 and 77 grain ammo is similar to the .308 reticles which are nto available in the TA31 line.  The TA11 .308 reticle does match up with 75 and 77 grain loads.  However with the short 11.5" barrel its not going to match up nearly as well as a 14.5 or 16" barrel using 75/77 grain ammo.  The TA11 also makes less sense as its so out of proportion to a SBR rifle.  It would make more sense to go with a smaller lighter optic that did not have BDC stadia built in.  A 2X or 3X compact ACOG would suit your needs perfectly instead of the TA31.  The TA31 is suited to longer ranges better, but this is really a shorter range rifle.  I am not a fan of the crosshair reticle as I cant use it in BAC mode but I like the circle and especially the triangle.  2X or 3X Compact ACOG with red triangle reticle.  If you want a magnified optic thats what I suggest for this rifle.  

I personally find any scope on a SIR rail to be too high.  However the Compact ACOG sits lower than the TA31 or TA11 so it helps out a little in that respect.

I agree 100% with the above post!!!!!!!!  Great info there!

I didn't know that.Even carrying the paperwork  will not allow someone to take their 11.5 to carbine courses in other states?

You can transport them interstate...  you just have to send the notification to the ATF and wait for their acknowledgement that you're transporting to return via the mail...

You need to take that document plus the copy of your 'license' with the weapon.

Also, don't try to take the rifle to a state that doesn't allow "assault weapons" or SBRs.

:)
Alex

I have entertained the idea of a suppressor, and believed it would be ideal on this short of a barrel. I'd like to go with KAC if possible.
I'm falling more to the con's on the setup. Since I only have one ar-15 at the moment with no plans to buy more in the near future.
The 14.5" seems like the best compromise. Plus the balistics look to be much better when coming out of a 3" longer barrel. I'd like to have my effective range further out, and match the Trijicon ACOG reticle pattern a little better.
Thanks for the information guys,
-Steve

Have you checked into the GemTech Bilock? [url]http://www.gem-tech.com/m4-96d.html[/url]

No I meant there are no reflex cans in the US and no quick detatch reflex cans anywhere in the world.

DevL
Yes the Fins remain convinced ther is not need for a QD can.
[url]www.canadiantactical.ca[/url]
It took a huge effort to get them to fit a decent system to retain the A2 (or KAC) FH.  I have noticed however that there are very few legitmate reasons for a QD mount.  There are still enough reasons that I'd like one - but not enough that I feel the relfex can if not a valuable addition.
[img]http://photos.ar15.com/ImageGallery/IG_LoadImage.asp?iImageUnq=13119[/img]


Edited to add - The KAC Mk11 Sound Suppressor could qualify for a QD reflex can...

I wonder what these IDF guys use in their Colts.
[img]http://www.isayeret.com/units/land/intel/tzasam/tzam.jpg[/img]

M193? Or SS109? IMI makes both.

I hate to be a killjoy, but I see several major cons.
1.  Ballistics suck.  Unless you are using some exotic ammo, your fragmentation distance on the bullet is maybe 35 yds.  Check the ammo faqs for specifics.  You can hit things at a greater distance, but it likely will not have the desired effect.

2.  Unless you just like the looks and are getting it for fun, you are way overpowered with the TA31.  Since you said you are looking at this for CQB distances, why get a 4x optic?  I am inferring a dislike for batteries and that is why you don't want an Aimpoint or Eotech.  If that is the case, get the 1.5x Compact ACOG with a triangle reticle.  You won't have too much magnification and it will be plenty fast on target in day or night.

3.  Consider getting one of the pigtail gastubes that wrap around the barrel.  Also, plan on having to tweak the system to get it to work right and plan on malfunctions if you switch ammo.  With the barrel lopped off just past the gas port, lack of pressure is a problem.

4.  Here are some quotes from www.isayeret.com, the IDF special forces website where the pic came from:

"Ever since its first introduction in 1987, the sawn off CAR15 was an immediate success within the IDF SF community. Not so much for its inherent concealment tactical advantage, but rather since it was a huge status symbol, especially since in 1992 the 14.5 CAR15 become the standard issue weapon in all infantry oriented units, including both SF and regular. So carrying a sawn off CAR15 not only meant you are a SF operator but it also meant that you are a member of one of the more prestigious CT units. The sawn off CAR15 was such a success that soon many high ranking IDF officers have adopted it, although they didn't had any actual need for the shorter barrel. Operationally, the sawn off CAR15 was used in various urban CT application scenarios, both covert and overt and. The weapon was such a smash hit, that many operators even used it for open field combat, regardless of its bad accuracy and limited range..."

and,

"Despite the good intentions behind its creation, the IDF home made sawn off CAR15 had one big problem. Like most infantry oriented aspects in the very unorganized IDF, the barrels' sawing project was done without a proper higher control and unified procedure. In the tests conducted by Colt before they began manufacturing of the Colt Commando, they found out that a 11.5 inch barrel length was the minimal M16 barrel length that still assured proper and reliable functioning of the weapon. Shorter barrel lengths would not allowed the building of sufficient gas pressure in the barrel, resulting in acute jamming problems.

Meanwhile in the IDF, the conversion of the CAR15 barrels wasn't done at one qualified armory, but rather in the SF units' own armories, often by untrained personal. The units' armors, unaware of Colt findings regarding the minimal required barrel length, and without any proper guidance, sawed off the barrel as they see feet, which usually meant all the way done to the front sight tower, resulting in sub 10 inch barrels. This over sawing of CAR15's barrel not only drastically damaged the CAR15 accuracy and maximum, which were less of a problem since it was due to be use in close ranges any way, but more importantly it caused the weapon to jam every now and then due to an insufficient gas pressure build in the barrel. The malfunctions problem didn't occurred to often, but during actual combat deployment one jamming in the wrong time and in the wrong place, might be very hazardous to one's health."

and

"While it was very popular in the IDF SF for more then a decade (late 1980's-late 1990's), currently, part from several samples still in usage by several CT units, most of sawn off CAR15 were taken out of service, due to their repetitive malfunction problems, and are no longer used by the vast majority of the IDF SF units. Even Sayeret Duvdevan operators, the past primary end users of the sawn off CAR15, no longer use the weapon. Instead the standard issue weapon for all the IDF SF units is the standard 14.5 inch barrel CAR15, often with a 1:7 twist heavy barrel allowing the CAR15 to fire the newer SS109/M855 ammunition (rather then the old non heavy 1:12 twist barrels that fire the M193 ammunition)."

I figure choices in firearm characteristics are highly subjective and while I personally see too many negatives and very few positives to such a short barrel length, go for it if you want to.  As long as you know the facts and still want one, have fun!  Thats what's nice about living in a free country!

Dorsai

All I see from your post is the problem with letting amatures try to convert a AR to a commando.

Did you also notice this?
[url]http://www.isayeret.com/weapons/assault/commando/commando.htm[/url]

The Israeli Police SF teams use REAL Colt factory made Commandos and Enhanced Commandos. They work great.
IDF SF teams had to make their own due to budget restrictions and a attempt to force the MiniGalili on to the Israeli army. Which was a cause of a lot of their problems. That and trying to use them in operations OUTSIDE of the urban areas they are designed for.

[img]http://www.isayeret.com/weapons/assault/commando/commando-3.jpg[/img]

Dorsai,

Factory 10 and 11" guns are utterly reliable - the gasbuster gatube is a much better option than the pigtail.

I don't consider the 75gr BTHP and like rounds exotic.

Seeing as the doorkicker SOF role uses the 10" 'Enhanced' Carbine faily exclusively for CQB...

Draw your own conclusions