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Posted: 2/14/2007 11:48:41 AM EDT
Ya'll feel free to comment or critique...
Philosophical mode "on" When we started out with the 556 decades ago, the system was realized by it's designers to be velocity dependant due to the small projectiles fired. They chose 20 inch barrels and 55 grain bullets to achieve the terminal results required. Muzzle velocities on this combo ran as high as 3300fps. As time passed we adopted the NATO 62 grain tungsten core bullet which was intended to offer better penetration at long range for SAW use. The 62 grain bullet reduced muzzle velocity to approx 3100fps out of a 20" barrel M16. Terminal performance began to suffer. Due to the increasingly urban nature of engagements, it was soon decided that barrels shorter than 20" were needed. 16" barrels were out due to problems with the fitment of issue bayonets, so 14.5" barrels were installed on the new M4. Heavy bullets/short barrels, a worst case senario for a 22 caliber weapon. What can be done? Glad you asked.  Personally, I like the idea of 16" barrels and 55 grain bullets, though the 20' rifle isn't the boat ore some would have us believe. In fact, a 20' gov't or A1 profile barrel is quite light and reasonably handy in all but the tightest situations. It does maximize much needed velocity. Philosophical mode off... |
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Posted: 2/14/2007 12:07:04 PM EDT
[#1]
Have you ever tried to...mount and dismount out of a vehicle in a hurry while underfire with a 20" barrel? Times have changed my friend...and so has the battlefield.
Didn't think so.... MajorAR |
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Posted: 2/14/2007 12:09:00 PM EDT
[#2]
Actually I have and don't think it's that bad... |
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Posted: 2/14/2007 12:42:06 PM EDT
[#3]
+1 and add a M203 |
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Posted: 2/14/2007 12:44:33 PM EDT
[#4]
Well, if you install a carbine telescoping stock on the 20 incher, it wouldn't be that bad.
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Posted: 2/14/2007 12:57:21 PM EDT
[#5]
I'm currently running a telestock on my 20" gun. It would seem to be a much better option than reducing the weapons terminal effectiveness by shortening the barrel. Still, my 16" AR spits 55 grain bullets at 3150fps. That ain't to bad... |
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Posted: 2/14/2007 12:57:40 PM EDT
[#6]
Yeah, but then all the guys on arfcom would make fun of you. |
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Posted: 2/14/2007 1:06:34 PM EDT
[#7]
I do not envy at all those people who have to get in an out of a HMMWV in a hurry. Why not have both available? Cary the M4, with 20 inchers in the vehicle? Get OUT, grab one or 5 if needed. In ARFCom style, carry both.
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Posted: 2/14/2007 1:48:35 PM EDT
[#8]
urban answer is the 50 beowulf. to quote, "Knock and the door shall be opened." if they don't open kick it in.
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Posted: 2/14/2007 1:57:24 PM EDT
[#9]
OK, that's a point taken. Maybe the larger calibers are the answer for our military needs if the short barrel is required. The 6.8, for example, provides a heavier round and decent mag capacity. For average Joe, shtf use, I still lean toward a longer barreled 556. |
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Posted: 2/14/2007 2:05:38 PM EDT
[#10]
they could design a new bullet with a thinner jacket that will fragment at a lower velocity. problem solved.
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Posted: 2/14/2007 2:14:40 PM EDT
[#11]
Or trying to get in and out of a Blackhawk. Also, the M16 is a PITAAAAAAA!!!!!!! to get in and out of armored suburbans with. M4s are much handier, lighter and more mobile. Not too mention the range at what we engage Tangos at now. I would venture that of all the CQB fights in Iraq so far, 90% of them were fought within 50m. Anything longer and thats why we have Designated Marksmen with M14's and beyond that, Snipers with M24s....and god forbid we need longer than that, the .50cal. |
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Posted: 2/14/2007 2:28:25 PM EDT
[#12]
The only thing I would disagree is that I never heard any complaints about the M-16/M855 combo. I heard of complaints about the M-4/M855 combo with the reduced velocity. I do agree that the M-16 should come with the collapsible stock and I have said that several times in the past. For me, the ideal Combat AR would be an AR with a 14.5" barrel, 1-4x optic, 6.8mm. |
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Posted: 2/14/2007 2:31:13 PM EDT
[#13]
I have wondered about just that myself. Keep in mind that I have no real world experience other than being a chairbourn ranger.
The other thing I look at is that most action seems to be with at least squad level and there seems to be some heavier weapons available, be it SAWs,DMs or that great old standby,a fifty mounted on a truck to tear the living s*** out of whatever needs to be torn up. I remember a year or so back a guard unit from my state of CT was on line to go to A-Stan at fairly short notice and a big stink was raised by some familiys as they had been told that due to shortages they were going with their "old" 20" M16s instead of the "beter" M4s. Not sure what their jobs were to be when they got there but except for the in close work and bailing out of vehicles I am not so sure that they wouldn't have been better off with what they had been training with. After the dust setteled they ended up getting M4s . In the same note I just finished watching "Flags of Our Fathers" and assuming that the movie folks got it correct (usually a leap of faith) it showed the beaches at Iwo and it seemed that fully half the guys had M1 Carbines or Thompson SMGs. Compared to the Garand a M4 is giving up lots of pure power with the ability to deliver more rounds but the M4 against the Carbine and the Thompson is a no-brainer! |
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Posted: 2/14/2007 3:21:27 PM EDT
[#14]
I love my 20"s they are just too long IMO, I love the handiness of my M4orgery, and it was easier to carry, but the loss of terminal velocity does concern me, so for me, from now on its Mid Lengths
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Posted: 2/14/2007 4:16:42 PM EDT
[#15]
That sounds good on the surface but can create other problems. The 556 was always light on barrier penetration and would be even more so with more frangible bullets. Also, if such a round was ever fired from 20" barrels at close range, bullet blow up and underpenetration might be encountered. I'm sure there's more to it than that, but those are off the top of my head. |
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Posted: 2/14/2007 6:34:42 PM EDT
[#16]
I have like the Canadian C7A2. The best of both worlds or split it and get a collasable stock and a 17 inch barrel.
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Posted: 2/14/2007 8:20:20 PM EDT
[#17]
If your standard round was a 62 gr. OTM type, along the same lines as the Mk 262 that would be a vast improvement. In my experience if you need to punch through cover you use a 240 or an M2. I'm of the firm opinion that ball ammo should be used for training or MG use only. If we're going to stick with M16 platform in 5.56, we need to maximize it's effectiveness. But Geneva limits us severely. Cost may have something to do with it also, not sure. I just wonder sometimes why I can shoot an American citizen with a HP pistol round or an OTM rifle round but I can't shoot some Hajii or other enemy combatant with it. Just my .02.
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Posted: 2/14/2007 8:31:23 PM EDT
[#18]
We need recoil assisted 50 caliber pistols!
 Seriously I have a 16" carbine and stock 55g FMJ... but the military unfortunately is using equipment primarily (and with good reason) designed to fight a major war against a Soviet style army. I think the easy and best answer is JHP ammo of some sort. |
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Posted: 2/14/2007 8:39:16 PM EDT
[#19]
I think something with NBT would serve well, or just have the tip of the cartridge with a cavity like the russian 5.45
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Posted: 2/14/2007 8:53:58 PM EDT
[#20]
You have a mix of bad info - and revisionist history there. |
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Posted: 2/14/2007 8:59:41 PM EDT
[#21]
The mission drives the gear, not the other way around.
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Posted: 2/15/2007 6:06:26 AM EDT
[#22]
Bingo! I've seen pics of A4geries over there, tele 20" rigs. And when we re-claim cities, there is a whole lot of house to house, room to room work where 50ft is a very long shot... |
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Posted: 2/15/2007 6:22:28 AM EDT
[#23]
You could always elaborate and clear things up...  When I typed the original post there was no intent to cover 40+ years of AR history in detail. I just wanted a brief overview to focus on ever shorter barrels and trends toward heavier bullets and their effect on a small bore systems effectiveness. |
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Posted: 2/15/2007 6:34:20 AM EDT
[#24]
For what I'd expect to to use mine, I'm quite satisfied my 14.5" with M193 will do the job out to 100m.
I like to think of it as a short range offensive weapon (whereas an M1 carbine or Thompson would best be a short range defensive weapon). I do agree that military M4s with M855 is not the best combination, but necessary because of logistical reasons. Fielding two types of 5.56mm en masse is just too much I guess. |
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Posted: 2/15/2007 6:44:42 AM EDT
[#25]
It would not be a vast improvement. Look at the 68 and 69 grain rounds. They dont have the range of the 75 and 77 grain rounds becuase of less stress on the jacket during yaw because of shorter length. You are saying we should go to a bullet with less mass to fragment and will fragment at higher velocities thus reducing its range. I just dont see the wisdom in that. OTM are used by the military currently so I dont understand the "I cant shoot Haji with it" comment either. In fact OTM is a military term to designate land warefare legal boat tail hollow point match bullets. |
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Posted: 2/15/2007 6:48:56 AM EDT
[#26]
To the original poster I think what needs to be done is continue the trend and go to all 75 grain ammo. Reduce velocity further to gain terminal effectiveness and precision and effective range from the shorter barreled weapons.
A 14.5" barrel with 75 grain pills is more effective than the 16" barrel with 55 grain ammo on human targets. |
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Posted: 2/15/2007 6:57:52 AM EDT
[#27]
Now add 3.5 inches and a hot load and your perfect. With collapsable stock of coarse. |
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Posted: 2/15/2007 7:05:56 AM EDT
[#28]
I understand the concept of increasing frag range, but won't that also have adverse effects on bullet drop at longer range? It seems to me that if short barreled weapons are a requirement (and I'm not entirely convinced they are required, as I said a 20" AR ain't no boat anchor ), then we certainly need to look at larger calibers. At the very least, lighter bullets would maintain some of the velocity loss due to the short barrel. I could understand a trend toward 55 grain OTM loads...I also look at cost factor. While it may not matter to Uncle Sam, 75 grain OTM ammo is expensive, especially nowadays. How can the average working man afford to stock and practice with it? |
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Posted: 2/15/2007 7:23:55 AM EDT
[#29]
The heavier bullets also have a higher BC than the lighter bullets so the bullet drop is not as much as you think. The 5.56 75 Gr. BTHP and M855 have a close enough bullet drop. Unfortunately the Military will never switch to a BTHP because of the price. The only thing you will see is what you have now with the MK262, which is being used in small quantities compared to the M855. |
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Posted: 2/15/2007 7:25:44 AM EDT
[#30]
No. Notice when people compete in High-Power at longer range they are all using heavier bullets (which run much slower than the lighter bullets). Why do you think that is? Could it possibly have something to do with much higher BC of the longer/heavier bullets compared to the short/light bullets. While the heavier bullets start slower, they keep their velocity better down range. The end results is a round that has superior terminal effects, has a longer fragmentation envelope, and is more accurate across the board. |
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Posted: 2/15/2007 7:46:10 AM EDT
[#31]
I know for sure, the hi power crowd isn't into 14.5" barrels.  The longer (heavy) bullets do have higher BCs, that's a fact. The 556 case would seem to be marginal to properly boost 75 grain bullets out of a short barrel. Bullet drop is a function of several factors, velocity and BC topping the list. My thought is that maybe we're working at the edge of the envelope with short barrels and heavy bullets. Just for discussion, it would be possible to make a higher BC (longer), tungsten core 55 grain bullet. Now that might be a real improvement, higher BC and low weight to keep the velocity up. I do see clearly that the 75 grain bullets have better sectional density. That may well be a substantial advantage. |
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Posted: 2/15/2007 7:51:35 AM EDT
[#32]
After the discussion so far, let's throw this out there for ya'll to kick around.
Would the optimal AR platform possibly have an 18" barrel, telestock and shoot a new, sleek tungsten core 55 grain bullet? Things to think about... |
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Posted: 2/15/2007 8:09:44 AM EDT
[#33]
The best combo would probably be the 18" barrel with the MK262 or Hornady 5.56 75 Gr. TAP. Kind of like the MK12 Rifle the Military is using. |
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Posted: 2/15/2007 8:14:14 AM EDT
[#34]
My next build may be emerging from the concept stage.
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Posted: 2/15/2007 9:38:00 AM EDT
[#35]
MK 262 out of a 14.5" barrel has 5" more drop at 325y than a 20" shooting the same round using the military zeroing method. Not enough difference to worry about. I'd rather have the lighter/shorter weapon than the extra 5".
Sure you could do that. But what would terminal perfornce be like? How would having a lighter bullet help with penetration once it fragments (assuming it even fragments)? |
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Posted: 2/15/2007 9:50:41 AM EDT
[#36]
Forest, thanks for your input on this. A couple of things come to mind in reading your last post. First, while I know ranges beyond 300 yards are unlikely, if a round has 5 inches of additional drop at 325, it will have a LOT more beyond that. Second, I'm going on the premise that everyone was happy with the systems terminal performance with 55 grain bullets from 20" barrels. I've never heard that penetration was a problem with M193. Was it? |
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Posted: 2/15/2007 9:50:49 AM EDT
[#37]
the canadians use the c7 20 inch barrel with an m4 stock it works for them i put one together its ugly but it works for me
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Posted: 2/15/2007 9:59:22 AM EDT
[#38]
Yes it will. But again ranges beyond 100M are uncommon, let alone 300M. Ever try hitting a moving target at 300M? It's even harder at 400&500M. Especially when you realize enemy soldiers don't walk in the open providing a perfect E type silhouette when they are under fire. Longer ranges are the domain of DMR's and support weapons so I don't see it as an issue.
There are no problems with M193. However, M193 is made from lead, you switch to a material that is not as dense and you could very easily end up with those problems. A 1gr particle of lead has a smaller cross section than a 1gr particle of tungsten. |
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Posted: 2/15/2007 10:09:03 AM EDT
[#39]
True, but M855 (tungsten) supposedly frags too when fired from rifle length weapons, right? |
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Posted: 2/15/2007 10:35:05 AM EDT
[#40]
Several things:
1) Bullet performance/fragmentation was NOT done intentionally. Sure, they had a 20" barrel and a fast projectile, but the key is the bullet's fragmentation. That was luck, more than anything. 2) M855 was primarily designed as a SAW round. Sure - M16/M4s can fire it, but that doesn't make it ideal. Recent combat has shown that, especially as weapons get shorter barrels and lower velocity as a result. 3) Heavy OTMs are a stop-gap measure. 4) M855 does NOT have a tungsten penetrator - it's steel. The answer, of course, is a new bullet- the 6.8SPC. It pretty much eliminates all of these shortcomings. In summary, the 6.8: * Has a bullet which will fragment out to around 250 yards. * Is less barrier sensitive that 5.56. * Performs well even with 16" weapons. It would be expensive to convert, but that's the best solution if we want our soldiers to have the best currently available weapons platform. |
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Posted: 2/15/2007 10:44:31 AM EDT
[#41]
M855 has a STEEL penetrator that is backed by plenty of lead. Also M855's terminal performance varies from lot to lot due to the complexity of the bullet's design. |
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Posted: 2/15/2007 11:42:13 AM EDT
[#42]
Try getting out of a heavily armored hmmwv loaded with gear with an a4 as I had to....  I still dont get why people continue to complain about the 5.56. If you place the bullets in the right place the target is going to go down in a hurry. If you shoot someone in the leg with a 460 weatherby they are still capable of shooting back. Its all about bullet placement folks.... And btw let me shoot you with my 7.5" and Ill use the heaviest bullets you can find too. See how well you do....  |
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Posted: 2/15/2007 11:51:08 AM EDT
[#43]
Zhukov,
A tungsten penetrator could work as an additional stopgap, as per penetration, couldn't it? As to terminal performance, why not the 6.5 Grendel? Better reach, better BC, and just as easy/cost effective to field, as the 6.8 SPC... Company that manufactures the .50 Beowulf makes the Grendel. Both have potential in today's, and near term, battlefields... If the military is going to keep the AR platform, they will have to remember, "All engineering is a compromise." Right now, the compromise between 55gr and 77gr, seems to be either the 62gr or the 68/69gr rounds. I prefer the 5.56 in 75gr or 77gr weights, as the OTM makes it a contender throughout much of its potential flight envelope. If I'm wrong, please educate me. Thanks, Carter |
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Posted: 2/15/2007 12:11:07 PM EDT
[#44]
Because as good as the 5.56 is there is better available ammo such as the 6.8 SPC. |
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Posted: 2/15/2007 12:11:38 PM EDT
[#45]
Penetration isn't what ails the 5.56.
Because the 6.8 is superior. They're close in terminal performance, but as of right now, the 6.8 wins out. There's the bigger story of the conversion from 5.56 -> 6.8 is much easier than 5.56 -> 6.5. I don't see much use for a .50 Beowulf for any application. |
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Posted: 2/15/2007 12:15:25 PM EDT
[#46]
That's a lame excuse and response. Mounting an unmounting was not an issue with a 20" A2. Maybe a little easier with a 16" , but by no means difficult. |
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Posted: 2/15/2007 12:20:59 PM EDT
[#47]
I agree. I carried an M-16 when I was in and no I never had to mount or unmount while getting shot at, but I never had any problems getting in and out of my HMMV and not even when I was the driver. When I drove, I placed the M-16 standing up on my left side right by my left knee and I was able to get in and out in a flash. If I was a passenger, it was even easier. |
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Posted: 2/15/2007 12:46:55 PM EDT
[#48]
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Posted: 2/15/2007 12:56:38 PM EDT
[#49]
My use of the AR system in and around vehicles is all limited to competition, training and use around hunting leases. That said, I never had any real problems dismounting either. I guess that's why I tend to favor the longer barrels. Terminal performance doesn't seem like a good thing to trade away, but I understand there are folks who view things differently and respect that.
The 6.8 is a great concept. I wish it would become military mainstream. I looked online at ammo last night and the cheapest I saw was Remington FMJ loads for about $16 for 20 rounds! I suppose one could reload a stockpile and practice with the 556 (or better yet, a 9mm). For now, I'm personally going to stick with 556 in 55 grain loadings from 16"+ barrels. |
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Posted: 2/15/2007 1:02:09 PM EDT
[#50]
You didn't look very hard For $16 you can get boxes of 110gr VMAX (one of the best for accuracy & terminal performance). $12-$13 will get you boxes of SSA Extreme. If you reload you can reload Extream or Rem FMJ for around $5/box 20 by reusing your brass and using surplus powder. |
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