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Posted: 11/6/2006 6:58:29 AM EDT
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16" vs 14.5" vs 11.5" barrels.... How much will length affect projectile velocity and accuaracy. I may have a line on a BM with an 11.5" bbl w/ 5" flash hider to keep it legal / non-NFA / SBR etc. I already have an ArmaLite M4C w/ 16" bbl and love it....looking for a blaster, not really looking for a sniper rifle. Thoughts and comments please. Thank you. |
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Depends on what capacity you want the rifle to perform.If yuor looking for longer range accuracy with velocity then a 20" barrle will do.For a defensive fighting carbine any barrel 11.5 to 16" will do as most combat engagements take place 90% of the time 100yds and under and 80% of the time well under 50 yds.In any event for the 5.56 to perform at its best you need a velocity of 2700 FPS,14.5 will do this out to 100 yds up to 120 when lighter bullets like 50 grain are used,140 to 150 for 16" and 200 yds with a 20". Unless your gonna SBR your carbine 11.5/5.5 is useless as its just wasted legnth that barrel can be ocupying,16" is great if you want the ability to change out flash hiders or muzzle devices,if your gonna leave the flash hider or comp alone then 14.5/permanent flash hider is the way to go as its the shortest legaly available with out SBRing it and now comapnys like CMMG offer 14.7 so a permanent A2 hider can be attached giving the carbine the true M4 look.I use 14.5/phantom..I like having no muzzle flash signiture. With a 14.5 you get the same accuracy as a 20" out to 250 yds the other legnths Im not certain but its gotta be a bit more for 16" and les for 11.5 when compared to a 20". I think youll love the 14.5..its 2" shorter than a 16" and just as accurate and you have something diferent.I have 3 Bushy carbines 1 14.5/phantom M4 profile 1/7,same thing as a 1/9 HBAR and a 16" pencil barrel..my wifes she likes them real light. My 4th AR is an 11.5/5.5 carbine whos barrel I just sold and Im putting a 14.7 CMMG SOCCOM profile with permanent A2 hider..thats getting a feed ramp flat top upper as well so I can make my SOCCOM clone.That 4th lower cost me a few hundred less than a complete rifle because up here we still have a ban and I dont want a neutered rifle so I had to pay to play it the way I wanted. |
www.ammo-oracle.com/body.htm#fragrange |
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www.ammo-oracle.com/body.htm#sbr Q. My department is considering using 10" or 11.5" barrels for our ARs. They are so cool, and everyone knows that all the real go-fast, high-speed, low-drag operators use SBRs. Plus, Robert DeNiro uses one in "Heat." What's the best ammo to use to poke big holes in the bad guys with these? ------- I'm right there with Ammo Oracle. But people still just go ape shit over these SBR's. And since we have the Navy Mk18 Mod0 just forget about it now. If SEALS are using Mk18's GAME OVER MAN, GAME OVER.  So honestly. WTF is the Mk18 being used for? If you tell me SEAL Teams are clearing out rooms with these, I'll buy that. So is that it pretty much? I'm being serious about this. (i'll return to sarcasm later) |
So if an 11.5" SBR can produce consistant fragmentation at over 100 yards this is inadequate for general police uses? Even though it will fragment at ranges beyond the average police sniper ranges? Your position and the position of the ammo oracle is a bit confusing there. Please explainwhy 100 yards of fragmenting range needs to be used by the patrol officer who in all likelyhood does not have magnifed optics on his rifle. |
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The Ammo Oracle knows what he's taking about. You'll have to ask him your question for a detailed answer. I've always been curious about the love affair many arfcommers have with these short barrel variants. If they are staying legal, that's $200 bucks you just paid so that you could PLINK around at the local range with your cool looking Navy SEAL gun. If my fellow archchair commando wants to sell me on the idea, that he wants a short barrel for "in close work" meaning he's going to TRULY use that thing for home defense I'll even buy that. I just don't know why arfcommers love them so much. If you read up on the Navy Mk18 Mod0 for exmple. SNIPPET: The short 10.3 in (262 mm) barrel length requires special modifications to reliably function. The gas port is opened from 0.062 to 0.070 in (0.16 to 0.18 mm). A one-piece McFarland gas ring replaces the three-piece gas ring set. The standard 4-coil extractor spring is replaced with a commercial off-the-shelf (COTS) 5-coil spring. An O-ring surrounds the extractor spring. /end snippet All that hassle cuz you want to be cool. 
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for 5.56, get the longest bbl that you can w/out sacrificing your utilitarian value of the AR--i.e.: get it as short as you want, as long as it fits your circumstances and you dont trade off one benefit for another 'benefit' persoanlly, i would prefer the 14.5 or 16 over a non-sbr 11.5 for the additional bbl length, w/out an elongated, less useful 5.5in FH whose job could be filled w/ a 1.5in FH...but thats just me 
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Says the man with the Delta Force video game logo as his avatar. |
 You should have seen the action I got when I had "1st SFOD-D" under that logo instead of "The Unit". Of course is was only CitySlicker that had issues with it. With all the action in the GD, it gets boring around here, so markm and I have to get people excited about something. So, for today, I've decided SBR's are stupid for civilians. Unless your really into Delta Force video games or the movie Heat. Not a hater, just curious why people choose to go the SBR route. |
Not picking on you directly, you just happen to post that. It turns people off. Serious people who come here looking for info (and maybe to contribute some good info) walk right back out the door when they see stuff like that, because unless you personally know the person you are directing it too, you are assinine to presume to know how or why they want or will use a particular setup. |
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Accuracy and velocity (as well as lethality) are functions of the barrel length. A bullet accurate and lethal inside 100 to 200 Meters may lose enough of its velocity at 300 Meters and beyond that the group will start opening up. To be lethal and have terminal effect you have to HIT the target. Not much of an issue inside buildings or in alley ways. If you're on a road you want the round to have long enough legs to hit some knucklehead overwatching his IED Kill zone, while providing a small enough group to hit him in the melon if the only thing he's exposing is his head and shoulders. Only hits count. Only center hits kill now. |
This is for you (unlike above). This is NOT GD. This is a tech forum. Take the games back to GD. The Tech forums are meant to be a much more serious area than much of the rest of the board. |
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Ammo oracle is not a "he" as in "The Ammo Oracle knows what he's taking about. You'll have to ask him your question for a detailed answer." It was written by multiple people,2 male one female, and one of the male authors is a friend who lives down the road from me who I have discussed things like that with at his home. I happen to know that the 5.56 Hornady TAP loading was not even in the spotlight when that web resource was first written. It was a myth people didnt believe existed. Now dozens of arfcom users have this ammo and its availbe for low prices to any LE officer and any civilian who wants it can get it if they look hard. I know the consensus was to use M193 at the time it was written and ideas and available products change. I am asking YOU why a rifle that has a fragmentation range in excess of the range anyone is going to use the rifle is a "TOY" and not a viable general purpose barrel length for civilian or LE use in the United States. I would like an answer to that and not more evasions to the question at hand. WHY IS 100M NOT AN ADEQUATE RANGE OF FRAGMENTATION FOR LE AND CIVILIAN USE? |
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Man! I can't imagine using one of those shorties inside the confines of a house. When we were shooting these High/Low criss cross shooter drills in class last weekend, I got under one of those shorty ARs. OUCH is the blast harsh on those... even with ear muffs on. 
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If it helps clarify....it may be for my wife.... I also tend to think that a 11.5" bbl with a big FH is silly, I do agree that it is better off as an SBR, BUT if the price is right, I am very tempted to overlook the FH. It is what it is. For our (re: her) purposes, no shots over 100 yds, and it would use M193 or M855 or equivilent loads. So from what I am reading and hopefully understanding, M193 would still fragment and accuracy would be acceptable at 100yds and under. AR gurus / jedi - thank you for your replies. |
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I am going through the trouble and expense to SBR my AR. 1. So I have less of a chance of smacking my 7" suppressor into a doorjamb when mounted on a 14.5" barrel. 2. To move the center of gravity of the rifle back to where it handles well with a suppressor attached. 3. Because I only carry Federal 55gr. BTHP TRU in my magazines. 4. Because I can put any upper I want on it when I go to the range for "fun" time. I am working on getting #3 changed to 75gr. TAP. Hopefully I will get a chance to go out to the range with my suppressor guy. If I like the "reflex" style can he has, I may have him rework mine so that I can still run my 14.5" barrel and have it suppressed. If you are building a NON-NFA weapon, there is NO REASON to have a short barrel and long flash hider. Get a 14.5" w/phantom or Vortex and you have the best all-around legal barrel length. You can even get a lightweight version if it's for a smaller shooter. |
No M193 will have a ~45 yard range and M855 ~15 yard range and 5.56 TAP has 100+ yard range for fragmentation threshhold. |
The MK18 is being used for whatever the individual Operator wants to use it for. It's being used in the CQB role (replaced the MP5) to being used in the open mountains of Afghanistan were the ranges are unlimited. The shorter barrels are a lot easier to manipulate in CQ or in/out of vehicles. Some Platoons SOP is to run suppressors. A 14.5" barrel with a can gets a little lengthy for most tasks, the shorter barrel with a can is about the length of a M4 w/o a suppressor. Too many people get wrapped up in "ballistics". Shot placement is everything. A BG will not know the difference if a bullet that went through his head or CM was either going 2,400 fps or 3,000 fps. 
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That info is from when Crane was chopping standard M4 barrels. Listed are the modifications that they had to do to make a standard 14.5" upper run when shortened to 10.3". Complete uppers are now purchased from Colt and LMT. The "Crane Kit" is not only used on the MK18's, it's also used on all of SOCOMs M4's. |
Yeah, I would've thought that Delta Boy (TheMocoMan) would have replied since I answered his questions. I guess that people around here are more interested in BS info than facts. I guess we need to stop spreading the truth and tell more BS stories Combat_Jack. Maybe we'll get some replies. |
oh I like that. "Delta Boy" that is. I'm trying to behave that's why I didn't post back in this thread. But since you dragged me back into this. Let have an explanation of the Pirate Badge/AvatarAre you the chubby one in this picture Pirate Boy?  
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    "shitter commando" or "commode commando" - the most elite of the elite. Great pic. |
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Quoted: So if an 11.5" SBR can produce consistant fragmentation at over 100 yards this is inadequate for general police uses? False. Consistant fragmentation at over 100 yards is adequate. Even though it will fragment at ranges beyond the average police sniper ranges? See first answer. Your position and the position of the ammo oracle is a bit confusing there. Please explain why 100 yards of fragmenting range needs to be used by the patrol officer who in all likelyhood does not have magnifed optics on his rifle. I don't have a position, I had a question. The Ammo Oracle has the beef with SBR's and Law Enforcement agencies using them. I would say your probably right, Jow Blow Patrolman will probably have a regular AR-15 Carbine type and not a magnified SDM-R type of weapon. Hell, he'd probably be damn lucky to even have an AR15 in the squad car. |
=================== Well put. I'm putting together a 6.8mm SPC Middie CMMG 14.5" w/Vortex G6A3. From what I've seen and read, that seems just the ticket for my purposes. Can comes later after SEI comes out with their dedicated shorty 6.8DC unit. |
When did they start doing those? I thought they only had 16" MedCon ones. |
Several agencies here have carbines in the patrol car and most of those are 16" not for ballistics purposes but for paperwork/legal purposes. |
| Agencies with DRMO M16s might as well put shorty uppers on them...but often the short barrels will not fit in existing rifle racks. Believe it or not a lot of military and LE specs for rifles demand that they fit existing rifle racks. Putting the cart before the horse. |
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