I know this has been battled out here and there in terms of velocity loss vs. compactidness (I think I just made that word up), and I can see the argument for the small size if you are cleaning house, literally.  And if you are LE/military and genuinely have an 11.5" barrel.

However, I seem to see quite a few non-NFA 11.5" uppers for sale, which of course include a 5.5" flash suppressor.

Now what is the purpose of this?  Seems to me like you get the worst of both worlds: decreased performance and no change in overall length.

So what gives?  Just a collector item?

I like the 11.5" shorty on my transferable Colt 614 because it is both flashy and loud. I've mounted an A1 flash suppressor on mine.

The 11.5 + a tacked on 5.5" brake makes it look kinda like an XM177E2 for foolks that are into that.

I plan on building an 11.5" gun for home defense. I will mount a AAC M4-2000 sound suppressor on the gun to eliminate muzzle flash and reduce the report to a level tolerable indoors. I have 2 16" ARs, but with the can mounted, they would be far to long to maneuver indoors. I will use only hollow points for defensive purposes in the shorty, so the wounding capabilites will not be as reliant on velocity as would M193.

TA - good idea.  As such suppressors are verboten here, I had not considered such a project.

The main reason is look really COOL!!!!!
Because 16 inches is 16 inches. The longer supressor may help reducing noise but in most cases the loss in velosity isn't worth it.

So you are going to go ahead and decide to use ammo that underpenetrates on purpose, right?  I hope this was done for consideration to your neighbors because you would be better served with 75 or 77 grain OTM bullets if you want improved wounding capabilities.  Your idea to use a conventional HP will give a decrease in wounding potential, which is fine so long as thats what you intended.

Also why the comment on using hollow points instead of M193 because M193 is reliant on velocity?  M193 still fragments at home defense ranges so why the concern?

I have a couple uppers like you mention. I bought one of them used with the intention of using the upper receiver to build a clone of the M16A1 I was issued in the Army.
I ended up likeing the look of it, so I kept it as is. It shoot very good; I was surprised at it's accuracy.
I have a second one that is basically identical to the first one, but this time I purchased it because I wanted the pre-ban lower. This upper is just sitting there.
I am a civilian. I am a sport shooter. I am not an armchair commando.  I don't care all that much about terminal performance and milking the last tiny bit of performance out of the cartridge. If I wanted to do that, my ARs would have 24" barrels.

DevL:

Does the M193 still perform as well at 11.5" velocities?  Isn't it something like 50fps per inch of barrel lost?  Is that enough MV out of 11.5" to make it tumble and fragment?

Thx!

Ed

Looking cool.

I think this is something that happens to your intestines! [LOL]

I believe the 11.5 inch with 5.5 inch suppressor really has no other purpose than looks.

IMO, I believe at short range a bullet designed to fragment (hollow point) will always be more effective than a FMJ (unless attempting to penetrate barriers). Especially out of 11.5 inch barrels.

1. less penetration, through walls etc, but still more than adequate to instantly stop the aggression at close range.
2. Reliable fragmentation.
3. And probably more accurate, not that that makes any difference at 0-25yds.

I think this is an excellent choice. A 16 inch would be too loud indoors and too long suppressed. An 11.5 inch would be very effective indoors and managable with a silencer.

Is it okay to shoot HPs through an AR silencer??

Other than Thomas_A_Anderson's use of a silencer, this is all I could think of, thus the post.

Here Is The Use Of One !!!!

[img]http://atlas.imagemagician.com/images/felloffthetruck/bushy.jpg[/img]

The 11.5 with long flashhider is a throwback to the Vienam era XM177's. Really nothing more than nostalga, the 5.5in length is to make them legal, but the originals were close, something like 4.5in. Even those were just a expedient, to try and keep the people who carried them from being blinded by their enormous flash at night. It obviously counteracted the purpose of having a short barrel! 14.5in barrels didn't appear in the Colt Catalog until 1970/71.

Personally, I don't know why anyone would want an 11.5" with a permanently attached 5.5" flash supressor.  Bushmaster has 'slip-over' type flash supressors that screw on a 16" but give it that 11.5 with a 5.5 look.  Thats a far better option, IMHO.  You get the velocity, but it still has that classic look.  OTOH, if you have a SBR or a MG to put it on, an 11.5" with only a birdcage is excellent for moving about within the confines of a house or building.

"Does the M193 still perform as well at 11.5" velocities? Isn't it something like 50fps per inch of barrel lost? Is that enough MV out of 11.5" to make it tumble and fragment?"

I am sure this has been discussed many times before, and I am sure this info is available elsewhere, but...........
Here is some chrono data I gathered with my own ARs. Ammo was Winchester White Box, 55 grain. Results are three shot averages.

11.5"         2558 fps
14"           2847 fps
16"           2894 fps
20"           3012 fps

So, as you can see, you lose a lot of velocity with that short barrel. I would say that based on everything I have read, you would not get reliable fragmentation or tumbling with M193. If I was going to be using this barrel length for self defense, I would use a commercial hollow point or possibly a soft point.

One of my instructors at Gunsite uses an 11.5" barrel M16 for SWAT operations. They use Federal HP. His thinking on the barrel length is two fold. One is that it is much easier to manuver inside a house with a shorter barrel and two is that with a can on it, it is only about the same OAL as a 16" carbine without the can.

I couldn't agree more.

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]
[img]http://www.imagestation.com/picture/sraid58/pa9cf47990a2721bc95c0def56a5685b8/fc681ada.jpg[/img]

So will the 75gr black hills be the best home defense load for shorties?

I am having my class III dealer here build me a 7.5 inch AOW.  Ill have to ask the intruder to wait while I put on my hearing protection before I fire, of course.
Gonna save up the dough to pay the $200 tax plus whatever a suppressor costs.  Anybody know where to get one cheaper than a $500 Gemtech?

Hey, 444...

When you throw around that "50 fps per inch of barrel lost" figure, are you talking about a barrel that is an original length of 16" or 20".  I am interested because I have a nice 16" upper (peep sights) and wish to build a long range upper and wonder about velocities comparing the 20" barrel to the 24" barrel.  Any thoughts.

I guess I should of made a new post...

Oh well,

Happy shooting

Yep!  The 75 grain ammo (or heavier) will do wonders for short uppers.  Even the 10'5 inchers are getting wonderful results with the heavier loads for CQB environs.  These bullets will fragment at far lower velocities than the 55 or 62 grain ammo.  

Scott, at best you'll get 100 fps from the longer barrel. Its not worth your effort. You should just get a 20, they are better handling. I think I am going for 18 or so.

If the AWB drops couldn't you just build an AR15 pistol with an 7.5" upper w/vortex flash hider and use 77gr ammo.

The shoulder stock is a very nice thing to have. They are your friend, and the reason why a carbine is easier to hit things with than a handgun.

If you want a 7.5" barrel, fine, but the buttstock is worth the 200 dollar tax for a SBR.

...And I had trouble adjusting to the look of a 16" with a standard stock! Suppressor or not, that thing looks twisted.

ArmdLbrl, I agree with you about wanting the stock. That's why I prefer M4 with an 14.5 barrel and collasped stock. As much as I like AR's I would probably just use a handgun if I needed to take care of someone within my home. It's hard to beat a handgun when trying to use another weapon for the same role as a handgun, especially an when using an AR.

Leadfoot, what do you mean by "beat a handgun"?

I want a weapon that has a hgih wounding potential and can penetrate soft body armor.  My "rifle" gives me both.  A pistol gives me neither.  No matter what pistol you have and no matter where you hit him, barring a CNS shot you better be ready for some hand to hand because a pistol will not stop a determined adversary before he can tackle you and beat/stab you to death.

A pistol would not be the way to go compared to an AR11.5" with a heavy grainer.  The above post says it all!  I am curious also what the velocities would be using the 75 grain and up ammo out of an AR (aow) 7.5"pistol?  I would think miserable.  Frag reliability would seem sketchy at best.

I have to think there is some significance to this.

I'm doing this from memory also so the numbers won't be right on.

I believe from the Marshell(?) "One shot stop" index (which I know a lot of people think is bogus, but I'm only considering the significance of documented shootings).

For the chart I have the .223 has over 100 actual shooting events where a 45gr HP stopped the aggression in 1 shot (claiming a OSS effectiveness of 100%).

I just have to think this gives some credibility to a lighter faster Hollow point at close ranges with a short barrel.

Seems to me at 20 yds from an 11.5 inch using a 45 or 52 gr HP at 3000-3100 fps would be extremely effective at stopping an attack with one shot.

I'm no expert and I'm probably totally wrong, but I still can't fully accept the idea of very heavy slow hollowpoints for use with SBRs.

The Heavy HPs I'm sure are very effective also, but there are several reasons I MIGHT choose a light HP over a Heavy one out of an SBR.

1.Velocities out to 50yds (or higher) are probably well over fragmentation velocity for a HP (different than FMJ).
2.Doesn't require a 1/7 twist which is harder to find and (I have heard) wears out faster.
3.Ammo is more available and cheaper to buy.
4.Less recoil ???
5.Flatter tragectory (may not apply to SBR, but still worth noting if you really need to take a longer shot).

Not just 'think' that but have proven it using M&S's own publishings.



No it doesn't.  To M&S if you got a boo-boo and stopped your agression - then that counted as a one shot stop.  However if it took 5 shots to the torso to stop you - then that incident was NEVER considered even though it shows a failing of the round to stop the agressor.

See the problem?


Seems to me you don't know anything about the field of Terminal Ballistics.  Head over to [url]http://www.firearmstactical.com[/url] for a great introduction.


Well if you're not an expert, and don't even follow the latest publishings how can you justify putting spewing out a position which contradics those of the experts (such as Dr. Roberts)?

7.5" is WAY to short for ANY .223 load.  Hornady only recommends the 75gr down to 11.5".  Their tests for TAP in 8.5" barrels only include the lighter rounds and even with the lower velocities they don't have the penetration you need for reliable incapacitation (12" minimum).

No, I don't follow all of the latest data and I probably should. I do have another Full time job and it is completel unrelated to firearms (that might be one reason).

I understand the debunking of the M&S data, but you can't tell me that those 100 cases or even 50 were one shot stops because someone got shot in the finger and ran home.

If I followed  ALL of the latest publishings than I would probably be an expert, wouldn't I?

I'm here to learn, I'm not trying to debunk any High profile ballistic expert.

From the LIMITED amount of reading that I have done. The major flaw with lighter hollow point (to soft targets) is that they fragment too quickly and only penetrate 6-8 inches in ballistic gelatin. This is a major downfall of the round at combat ranges 50-200 yds, but at the ranges you would use an SBR 0-50 MAX a light hollowpoint penetration is plenty, and if the bullet did hit a bone and explode and still not hit any vital organs (which is still doubtful at 7yds) than it might require a second shot.

A heavy hollowpoint will penetrate 12-15 (from memory) inches of ballistic gelatin and reliably fragment at lower velocities. How low? Has this been tested for 7-11 inch barrels? Most of the data I've seen is using 14-16 inch barrels (but I haven't seen that much). More than likely It would do very well at 0-50yds.

My point is. I realize all of the ballistic data says that these heavy bullets are magic.
But I seriously don't think it is necessary to reconfigure your weapon (to 1/7), purchase this more expensive ammo, and then have to wonder if you can make a 100 yd head shot with a 77 gr bullet and a Eotech because the bullet will drop too much (out of your 11.5 inch barrel).

When a lighter hollow point would be just as good (in an SBR) and you don't have to go through all the modifications.

Hey, I'm discussing on a discussion forum, I'm trying to have fun and learn. I didn't realize you needed a PHD in  Ballistics to post a stinkin' opinion.

Blow me out of the water with facts and documented real life shooting events(and don't tell me to go read another website, because I already spent too much time on this one).

Devl,

I take it from your argument about pistol vs. rifle that you have a bayonet mounted at all times? [;)]

Another thing to consider (and we are talking about personal and home defense here).

Is because the 75-77 gr bullets penetrate so well. Odds are they will effectively penetrate walls better than the light HPs. This is something to consider.

Also remember (FWIW, coming from a dummy). The reason pistols are so ineffective is because the velocity isn't there to produce the shock required to instantly decapacitate. So what happens when your .223 bullets get heavier and heavier and the velocity gets slower and slower (a la 7.62X39).

Here I'll through some interesting reading out there too (probably outdated and debunked though).
[url]http://www.olyarms.com/223cqb.html[/url]

I am planning to use 64gr Winchester PPP for its greater effectiveness from shorter barrels and its decresed likelyhood of penetrating building materials. Since when is it known for underpenetration? I have personally, very effectively, killed deer with it .

M193 and other ball ammo is very dependant on velocity for reliable fragmentation in tissue and therefore effective wounding capabilities. A 5.56 round loses over 300fps from a 11.5" bbl compared to a 16" tube. HPs are more reliably effective from shorter barrels regardless of range. Also, M193, at a lower velocity, is less likely to fragment on contact with hard surfaces and therefore more likely to penetrate through walls.

blikbok, I mean if you're looking for the weapon that's easy to handle indoors then it's hard to beat a handgun. I never said a handgun is better than AR for ballistics.

Hell, I would feel better putting the enemy down with an AR anyday over a handgun, but I feel more comfortable using my handgun.

That's all. But I do prefer the 14.5" barrel over the 11.5 barrel because I feel it's gives the user more options.

I would rather have a good knife than a bayonete on an SBR. [;)]

The 75 and 77 grain ammo has been tested in G36C barrels which are only 9 inches and they still fragment at CQB distances.

Please dont reference the one stop shot data from M&S.  I can look real mean and thump some someone on the forehead with my finger and they will cease hostilities 50% of the time.  Just because someone decides to stop does not mean that YOU are what stopped them nor your particular load you shot them with.  You can give up because you are scared of seeing your own blood from a gut shot or you can fight on with 3 rounds in your lungs.  You cant see anything in the M&S stats, they are meaningless.

As for the heavy .223/5.56 rounds.  They have plenty of temporary cavity if thats important to you.  Also they have similar external ballistics as .308 fired from a 20" barrel when the 75/77 ammo is fired from short carbine barrels.   So saying you cant make a head shot at 200m due to bullet drop is not a realistic arguement.

Two things a 11.5 does better than a 14.5 are fit under a coat, and get into action from the drivers seat of a car.



I don't know about this. Look at all the SF guys doing executive protection details in Afghanistan and Iraq. Those are NSWC Crane built 10.5" ARs. What are they using?



The fragmentation gets more and more violent at lower and lower velocity. Because a heavy 5.56 bullet has to be so very long, and length is the factor behind tumbling. Since lead and copper are not the strongest metals in the world the stress on that long skinny bullet then causes it to break up. There is a point I am sure where the bullet becomes too slow for this to work, and not enough stress is generated to snap the bullet in two, but we havn't found that point yet.

They are using the 77gr loads at a higher velocity.

I can tell you what Hornady has published,  10.5" isn't that far off from 11.5" so I'd expect it to be useable for CQB (+) [the 11.5" hits its fragmentation range around 75y - the 10.5 will be a bit less].  However my comments were based on those guys looking for 7.5" barrels - Hornady did not publish data for any tests of 8.5" barrels with 75gr (only the 40, 55 & 60gr TAP rounds).

However DevL is correct, Dr. Roberts has indicated the heavy loads perform adequately in the G36Cs and HK53s for CQB distances (3-10M).  

Allrighty then...let me try to understand this...

the 7.5 inch barrel on my AOW (+3 inches of comp) will produce velocities with 55 gr GI ball of 2100 fps.  (this is from several range reports of the DPMS Kitty Kat Panther)

Oddly enough...the chronograph seems to show heavier grains to be moving faster out of the muzzle.  I dont understand how so I am ignoring it for now.  Maybe reduced blow-by cuz of the longer bullet?

Anyways...I can expect about 2200fps with the 75gr Black Hills HP load.  I have a 1:9 twist barrel on the AOW, so it should be just enough to stabilize it till it hits some soft tissue.

Is this a better round for incapacitation than the hyper velocity lightweight HPs?  They were designed for varminting, it looks like.

Thanks!

These bullets were fired from an upstairs window, into a 20 gallon drum of water, about 6 ft below the muzzle. The rifle has a 11.5" 1x9 twist Bushmaster barrel, and a MOUT suppressor on the front.
[img]http://www.imagestation.com/picture/sraid58/peb55bc51a12ede4da188e4b63a57dd94/fc681ad8.jpg[/img]

Seeing as I do not have to play by any rules, I will stick to HP or SP ammo. The fragments at the left are Speer 55gr SP, and the pile of "stuff" is a Hornady 52gr HP. The top bullet is a 270 Ballistic tip, recovered from a deer, the bottom is a 9mm Gold Saber.
[img]http://www.imagestation.com/picture/sraid65/p1b0135a0fe2757a44f1234d41570e6ad/fbf2258f.jpg[/img]

I realize the M&S stuff is pretty much crap. The only point I was trying to make with it is that there has to be some statistical significance to a 40gr HP being 99% effective in 125 shootings (period that's all). If the round was crap despite the possibility that 50 people ran away with a broken pinky nail. The numbers would still reflect it because there are so many accounts for this particular round.

That said I probably wouldn't use anything less than 52 gr HP/SP (I've also seen these do major damage to deer out of a .222 at 100yds).

Oh, and I relent on the head shot at 100yds with 77 gr HP, I'm sure you are correct DevL.

I am curious how much correction you would have to make if your Red dot was sighted for 25-50yds and you had to make a 100 yd shot with a 77 gr bullet. Does anyone have any charts?

OK the M&S data is flawed in the way its presented.  If 500 people got shot and 400 of them were shot 5 times and were not stopped and 100 of them were shot 1 time and stopped because they didnt want another 4 bullets in them the M&S data would be 100% 1 shot stops.  Also becuase the number is so SMALL its statistically insignificant.  Yes I said small.  The funny thing is how the street results they propose as fact and an indication of stopping power will often track so reliably with velocity as to be impossible.  What I am saying is the data is not only meaningless its also probably manufactured.  By that I mean its made up.  A lie.  A falsehood.

If you sighted in at 50 yards and wanted to make a head shot on a human with 75 or 77 grain ammo at 100 yards you would not need to hold over or under.  You would get your kill right there.  A difference of about an inch or so with the short barrel.