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Posted: 8/27/2004 7:28:47 AM EDT
[#1]
Hornady 75gr TAP Even with the heavier bullet (75gr) and lower fragmentation threshold (approx. 2300 fps) you'll be lucky to reach that velocity at the muzzle. 10.5" barrels certainly have a cool factor, but are generally poor performers against real threats. |
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Posted: 8/27/2004 8:08:28 AM EDT
[#2]
Think Ruger 10/22 .22LR 
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Posted: 8/27/2004 8:18:52 AM EDT
[#3]
At what distance? |
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Posted: 8/27/2004 10:03:52 AM EDT
[#4]
75 gr. TAP rounds will reliably fragment out to 50 yards from a 10.5" barrel
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Posted: 8/27/2004 12:12:49 PM EDT
[#5]
Yes.
I wanna see real world results from a 10.5-11.5" barrel. Using USGI ammo. Inside 50yrds. |
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Posted: 8/27/2004 12:19:49 PM EDT
[#6]
I can't recall what jurisdication it was -- probably wouldn't mention it anyway, but while at Blackwater I conversed with an entry team cleaning their MP5PDW's......they said they were great and all, but they were finding more and more thugs with soft body armor on and the 9mm wasn't gonna cut it. They also said that their engagments tended to be less than 75 FEET -- from here to the other side of the room typically.
They had two team members with Colt 9mm M16's and they claimed to have been experimenting with 5.56 uppers in the M16's and found they could do the job AND punch the vests. FWIW..... |
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Posted: 8/27/2004 12:23:33 PM EDT
[#7]
Using USGI ammo? Meaning M855? You'll get a .22" hole that will widen out to the length of the bullet for a couple of inches as the bullet flips around and continues base-first. That's it. An 11.5" barrel will not get M855 above the fragmentation velocity floor at any range, and a 10" barrel is worse.
Using M193, you may have as much as 10-15m of fragmentation range, beyond which you'll get the performance above. I would *strongly* recommend a 75-77gr OTM loading, preferably loaded to military pressures (most civilian loads are loaded to SAAMI pressures, giving less velocity and therefore less fragmentation range). -Troy |
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Posted: 8/27/2004 12:25:44 PM EDT
[#8]
Troy: At what depth would it do the tumble? Thanks. |
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Posted: 8/27/2004 12:39:32 PM EDT
[#9]
It's a .22LR that can penetrate vests. It's the duplicate of the FN 5.7mm, except when Mk262 type ammo is used. Okay, okay, it's a very very strong .22LR.
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Posted: 8/27/2004 12:46:16 PM EDT
[#10]
I hear you.......but it's that or SBR'ed 9's, 40's and 45's that won't punch them at all.....  |
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Posted: 8/27/2004 12:54:04 PM EDT
[#11]
So why do we see so many 10-11.5 uppers over in the sandbox?
If it can't get M193/M855 up to speed, what's the point? I know about the space saving approach, but what else? Am I missing something? |
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Posted: 8/27/2004 12:56:55 PM EDT
[#12]
heres one we havent done in a couple of days...
You see them in the sandbox used by private security who spend most of their time in SUVs. |
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Posted: 8/27/2004 12:58:57 PM EDT
[#13]
I think you've become jaded....... 
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Posted: 8/27/2004 1:04:50 PM EDT
[#14]
Lumpy, Just tell yourself "TGIF". You'll feel better.  |
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Posted: 8/27/2004 1:18:38 PM EDT
[#15]
One major reason is because few people have ANY understanding of how bullets wound, how specifically M855 wounds, and the relationship that velocity (and barrel length) have on its wounding potential. Another reason is because 10" uppers are much handier to carry around and move in and out of vehicles, which is what many contractors do all day. Yet another reason is because no one tells them they can't have one, and 10" barrels look "high-speed, low-drag" and "bad-ass". Yes, there is some MallNinja-ism even in the military. Most soldiers (who know nothing about ballistics, but know plenty about carrying their weapon all day) lust after the short-barreled rifles they occasionally see the SpecOps guys using, and will aquire one at any oppertunity, so they can be cool. Much the same reason Osama carries a Krink, or why officers carry pistols: it's a status symbol. But, again, mostly it's lack of any real knowledge of terminal ballistics. It simply isn't taught. Soldiers fight with the weapons and ammo they're issued, and that's that. -Troy |
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Posted: 8/27/2004 1:21:23 PM EDT
[#16]
Alright.
That sounds good. I can digest that. |
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Posted: 8/27/2004 2:01:39 PM EDT
[#17]
Back in ye olde days of ar15.com, An employee of Crane NSWC used to post here and addressed this issue (this was years ago). He stated quite simply that these uppers were destined for the hands of highly trained operators for use at across-the-room distances i.e. "all CNS shots" (his quote). The 10.5" upper has obviously gained more widespread use since then.
He also stated that M855 would fragment reliably out of a 10.5" barrel. As co-author with Dr. Fackler of a paper on M855 fragmentation in ballistic gellatin, he probably had some basis for that claim. |
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Posted: 8/29/2004 3:14:17 PM EDT
[#18]
Thanks for all your input. I agree many times the "cool factor" outweighs the performance from such a short barrel. Does anyone have links to data, after actions reports from shootings? I am trying to maximize the 5.56 performance from this short barrel but would like to read facts rather than speculations.
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Posted: 8/29/2004 5:59:59 PM EDT
[#19]
As with anything, it has its limitations. If you know those limitations and stick to them, you will be fine. Some contractors know what they are doing and will use a short barrel where it is most appropriate, and some don't. In military circles, the CQBR is used just for that, CQB. It is for hunting in caves and buildings mostly. Shooting out of a vhicle is fine as long as the target is only a few meters from your window. In most urban environments, it will suffice. Anyway, ideally, it would only be used for fighting your way out of your vehicle and toward a place where a longer range weapon can be used more comfortably, (stating once again) ideally.
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Posted: 8/29/2004 6:36:09 PM EDT
[#20]
Seems to me that a sub-machinegun, perhaps shooting AP rounds, would be a better choice for shooting out a car window just before you exit. Lumpy196 posted a picture of an Israeli soldier a few weeks ago carrying both an M4 and one of the shorty’s you describe. Perhaps the Israeli army is the only organization with extensive experience with them. |
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Posted: 8/29/2004 6:41:06 PM EDT
[#21]
I really have a hard time understanding the problem with 16" OR 14.5" weapons deployed from vehicles. Having done that and trained on it rather intensively I never had many problems. Yes, you have to be muzzle aware, but that's important anyhow. I actually prefer the discipline a longer barrel requires and I CERTAINLY prefer the terminals. |
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Posted: 8/29/2004 6:44:46 PM EDT
[#22]
5.56mm still has far superior ballistics to any handgun ammo, even from a short barrel, if it is used at the appropriate ranges. Having stuff like Mk 262 ammo helps a whole lot in that regard. |
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Posted: 8/29/2004 7:09:41 PM EDT
[#23]
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Posted: 8/29/2004 7:16:59 PM EDT
[#24]
I never had a problem with 20" barrels myself, but I was in a Hummer, not an SUV like some of these private contractors. Did you know they issue M1 tanks a 20" M16? Try and get that out a turret quick. I read about some HMMWV drivers keeping sub-guns on their laps so they could spray the roadside. They were not intent on dismounting though, just driving by with no hands on the wheel. 
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Posted: 8/29/2004 11:21:02 PM EDT
[#25]
The chart above illustrates what I'm talking about. Both M193 and M855* happen to have the same terminal velocity threshold for reliable fragmentation: around 2700 fps. From a 10" barrel, you don't even get this velocity at the muzzle with M855, which is the only ammo that most contractors and virtually all soldiers have available to them. Let's not even mention the known problems with contruction variations with the M855's dual-core bullet design, which increase the velocity threshold needed for fragmentation. Does your lot of ammo fragment at 2700 fps, or 2900 fps? No way to know without testing, and even then, it often isn't consistant. M193 is much more consistant due to the plain lead core simplifying bullet construction.
Yes, but then you wouldn't look COOL!  -Troy |
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Posted: 8/30/2004 7:18:01 AM EDT
[#26]
As for barrel length in the sandbox, apparetnly lots of folks over there (light infantry, not contractors) have picked up surplus Beretta M12 and Sterling SMGs for use in the vehicles and only use their M-4s when they dismount. Those units who have access to MP-5s are using them in this role as well.
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Posted: 8/30/2004 10:15:55 AM EDT
[#27]
I think this is the Israeli gun I saw: 
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Posted: 8/30/2004 2:01:49 PM EDT
[#28]
That looks like a 7.5" barrel, which would be practically useless no matter what ammo you used at any range. I've never sen an Israeli carrying anything less than 11.5", but anything is possible I guess. |
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Posted: 8/30/2004 2:07:20 PM EDT
[#29]
I found some more chopped ones here: www.isayeret.com/weapons/assault/car15/car15sawn.htm The coolest looking one I've seen is a 9mm: 
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Posted: 8/30/2004 2:40:03 PM EDT
[#30]
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Posted: 8/30/2004 2:44:44 PM EDT
[#31]
Now I'm confused  Pat Rogers is talking about 10.5s over on TF. He says: "This is the best AR that i have ever used- ever. I would take this to a fight at any time."  Somebody please tell me I'm wrong about this. And hurry! It's in the Seal forum. |
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Posted: 8/30/2004 3:01:37 PM EDT
[#32]
I have been looking into the same data and the conclusion I have come to is to get the best possible effect from a 10.5 barrel you need to go to soft point ammo such as the 62gr power points.
Good luck with your shorty. |
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Posted: 8/30/2004 3:04:11 PM EDT
[#33]
Here is what he says: "...Black Hills with the MK262 Mod 1. It is not a death ray, but is sufficient for the distances at which this bbl. will -or should- be used at. The 10.5" bbl is- like all things- a compromise. It makes perfect sense while mounted or doing VBSS/ GOPLAT's and PSD's. The 14.5" barrel is a better- much better- general purpose length. The advantage of the MRP is- besides efficiency- the one minute barrel change, which gives a Shooter another option. Right tool for the right job." |
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Posted: 8/30/2004 3:30:56 PM EDT
[#34]
Exact quotes: "FYI. I have about 5k rounds through the MRP in 10.5" and 14.5" configurations- no malfunctions. LMT makes the best of the AR series guns by a bunch. There will be a story in SWAT shortly." "This is the best AR that i have ever used- ever. I would take this to a fight at any time." "The problems earlier were reliability and ballistic efficiency. The reliability has been solved by LMT, and the ballistic vodoo by Jeff Hoffman at Black Hills with the MK262 Mod 1. It is not a death ray, but is sufficient for the distances at which this bbl. will -or should- be used at. The 10.5" bbl is- like all things- a compromise. It makes perfect sense while mounted or doing VBSS/ GOPLAT's and PSD's. The 14.5" barrel is a better- much better- general purpose length. The advantage of the MRP is- besides efficiency- the one minute barrel change, which gives a Shooter another option. Right tool for the right job." Whats confusing about this Robert? |
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Posted: 8/30/2004 3:37:20 PM EDT
[#35]
Clearly, his comment wasn't directed at 10.5" barrels, but at the MRP system in general. But I also know that Pat is one of those few who does understand the ballistics of short-barreled rifles, and understands the limitations they impose. He also knows which ammo to use and what the performance envelope will be, and will choose such a barrel when he is likely to stay inside that envelope.
No one said that there's NO place for such a barrel, but it's not a "universally good idea" like some folks think. They are a specialty tool that requires specialty ammo and still have a very narrow performance window. As long as these are okay for your needs, great. -Troy |
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Posted: 8/30/2004 4:04:15 PM EDT
[#36]
It seems to me that when shooting at people some distance from your vehicle, rapid & total incapacitation may not be all that necessary. Even "10/22" wounds might convince them to go elsewhere, or at least convince them not to pile into their white Toyota P/U and follow you . . . |
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Posted: 8/30/2004 5:23:29 PM EDT
[#37]
That was on page two, which I hadn't read when I posted. edited to add: Lumpy don't kill me ! 
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Posted: 8/30/2004 6:37:34 PM EDT
[#38]
Um...okay.
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Posted: 8/30/2004 7:20:02 PM EDT
[#39]
lol...now why would I do that? Just helping a brother out 
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Posted: 8/30/2004 7:53:30 PM EDT
[#40]
I can accept Mk262 ammo changing the 10.5” barrel into a nice short range piece for clearing out a parkingspace for the SUV, but, "This is the best AR that i have ever used- ever” ? Then he says, “The 14.5" barrel is a better- much better- general purpose length.” = my confusion… Troy helped clear it up by saying, “Clearly, his comment wasn't directed at 10.5" barrels, but at the MRP system in general.” That makes sense now, I think 
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Posted: 8/30/2004 11:51:19 PM EDT
[#41]
I think you grossly misunderstand the thinking and motivation of the enemy we face in Iraq. Keep in mind that this is an enemy for whom their religion is the center of their existence, and that religion instructs them to kill Americans (who are assumed to be non-Muslim) in order to assure their place in the afterlife. And they FULLY believe this. Further, they believe that dying in the process of taking American lives gives them special status. When one of these guys is pointing an RPG at your Ford pickup, you damn well better be able to put him out of action, RFN!, or it may be YOUR charred corpse being bagged up and sent home. War does not lightly forgive mistakes of this nature, and the price of failure is very high. -Troy |
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Posted: 8/31/2004 3:50:48 AM EDT
[#42]
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Posted: 8/31/2004 6:34:42 AM EDT
[#43]
I'll IM it to ya.
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Posted: 9/9/2004 11:32:12 AM EDT
[#44]
The Oct/Nov issue of SWAT has an article on the LMT MRP system where Pat Rogers says the 10.5" barrel, "...offers some great advantages for certain missions...the shorter barrel makes for a much handier weapon. In this case, the ease with which the carbine can be deployed may mean the difference between winning and losing."
He goes on to say you better be ready to deliver multiple rounds into your opponent and MK262 is the round preferred. This thread has been a learning experience.
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Posted: 9/9/2004 7:31:44 PM EDT
[#45]
Remember: Pat knows to use Mk262 (77gr OTM) ammo in those shorties, and is one of the people who would be likely to get it if he needed it. Most folks over in Iraq are stuck with M855 exclusively (this is true of both military and contractors), and that's a VERY different situation.
Your rifle and your ammo work together as a system. 5.56mm ammo really isn't very forgiving performance-wise if you make changes to the host rifle. Pat is speaking and thinking in a specific context (being able to use Mk262), and that context doesn't apply to everyone. -Troy |
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