if you down a few posts from OP i posted the 10.5 velocities

its actually posted 3 times in this thread

i won pg 3

LOL you guys are too much. First the reports of longer m-16 barrels producing TOO much velocity and causing too many through-and-throughs. Now its not enough velocity. How do you guys fucking want it?

ETA: From what I have been told, they currently build some of the Mk18's from LMT uppers which I am fairly certain are 10.5ers. Don't quote me on that though.

ETA#2:

Hmmm.. that looks like an NSN number too me. And does that say MK18 Mod 0? Yup.

they should just give all the cool kids MRP CQB 10.5s

But...But those would clearly be inferior to an 11.5"

Just sayin'

Not according to "MWJ227"


looks like he diff had some "fun" with his 10.5 MRP

That's rad.

well 500/10 = 50(fps per 10th of inch)

.2 inches would be roughly 100fps as this is an estimate... i would guess its more like 80fps or so.

EDIT



guess i was wrong.

averaging the 10.3 veloocities versus the one 10.5 velocity is about 350 fps increase.

the one inch (10.5 to 11.5 is only about 200fps faster.

so at 10.5" you have about 50-60fps of error, hope the loads are consistent.
Anyone who sais a bullet is "too fast" is an idiot.  Too slow you wont frag, more speed = more hydrostatic pressure = quicker fragmentation, which is what causes the most damage from the m193 and m855 rounds.

well bro...stand in front of the MK18 and tell me what you think of the velocity numbers then....LOL

glad i decided on the 11.5in for my first SBR

Really?

Tell me you didn't just use that line in a debate...



 

+1

I originally was going to build 10.5" upper until I started seeing data like this. I went 11.5" and am very happy I did.

Really, considering the significant velocity and reliability advantages the 11.5 has over the 10.5 and considering that at only 1" shorter, the 10.5 really has no meaningful advantage in weight, balance or handling... going with the 11.5 over the 10.5 seems like a no-brainer to me and make me wonder why people (including the military) even bother messing with the 10.5"?

well then...stand in front of it bro... and then tell me if the velocity drop is a concern, lol

all i know is i cleaned house with a 10.3'' SBR at a USMC MEU (SOC) match against 14.5, 16'' 20'' varieties.
that was against 32 other shooters.  we even chrony'd a 22, that ran about 1100. i wouldn't stand in front of that
either.  don't be a Hater...lol  
each length has a purpose and was built for a reason. i wouldn't take a 10'' to a 1000 yard range.
i have other tools for that.

Not being a "hater" but the "stand in front of it and say that" argument has just been played to death trying to justify everything from the Five-Seven to concealed carrying a NAA .22 revolver...  I wouldn't want to stand in front of a Red-Rider given the choice.


You're never going to actually convince anyone of your view by saying that.


Sure, you did well with a shorty at a CQ match, it's short and quick.  I'm not bashing your choice of firearm, just less than impressed with your persuasive techniques...
 

First off, it was BSOG's chronograph and Mk 18 that were used in this, so we wouldn't be having the discussion at all if he hadn't cooperated.  And I know he's got plenty of other tools to grab that might be more appropriate to any given need  

His point that you don't want to be on the receiving end of either velocity bullet is a valid one. None of us are looking to get shot. Conversely, it is appropriate to discus the issues of terminal ballistics for those to whom it really matters.

I started this thread because I was very surprised at the drop in velocity between my 11.5" and his 10.3".  He's not concerned about it. I wasn't concerned, just surprised, so I brought it up.

I also started the discussion, because the rule of thumb of "~50 FPS" per inch of barrel length is clearly very incorrect for the 223/5.56. It wasn't for some of the other guns we shot. For example, suplus military ball (Argentine 1978) in 7.62x51 ran ~ 2750 FPS out of BSOG's 20" M60 (chrono'd one round at a time) and 2450 fps out of my 12.5" Noveske Leoonidas, which pretty much was exactly what I expected.

I also take issue with terming this a "debate."  You can choose to debate the relative effectiveness of the round; from my perspective I was reporting actual results of the tests. The results are not themselves debateable; you can disagree with them, tell me that you believe that there was something wrong with the equipment or the process, but the results are what we observed.

Anyone who wants to shjow up atthe event at the end of the month is welcome to. bring the guns and loads that you feel are appropriate and we will run them and compare them to other stuff we do the same day.  Otherwise, we're just arguing on the internet

Sorry BSOG1 but your arguments here do nothing to prove a 10.5" AR is a more effect killing tool...


By that reasoning, I guess a dick makes a pretty good weapon too because I sure as hell wouldn't want to be standing in front of one when it goes off either

This discussion is about a barrel's length effect on velocity and velocities effect on fragmentation. Would I want to be shot with a round of XM-193 that went straight through without fragmenting? Hell no but I would rather get hit by 2 rounds of XM-193 that passed through without fragmenting then 1 round that did.


Sorry but that has no relevance to what's being discussed here.

1. Your performance has as much to do with talent level as it does barrel length. While I'm sure the shorter barrel gave you some advantage, I'm also sure a good shooter with a 14.5" barrel would have cleaned house quicker then a less skilled shooter with a 10.5" barrel

2. You were not shooting live targets. Again, this is all about frag range and ultimately how frag range can effect a rounds ability to drop a live target. Same scenario, I wonder how many of your targets would have lived compared to the targets dropped by the guy using an M4?

Here some information
The OPs 11.5CL is actually faster than a noveske 12.5SS barrel
––––––––xm193–––––––––– x855
10.3––––––-2678––––––-2563 OP results

10.5––––––-2755––––––-2639 MSTN results

11.5––––––––2957––––––––––-2759 OP results

12.5SS––––––––-2948––––––––2836 MSTN results

14.5––––––––-3002––––––––––2886 OP Results
––––––––––––––2984––––––––––-2861 MSTN Result

sorry for the bad format

The velocity data reported is abnormal. I have never seen a (serviceable) 10.5 barrel chrono that low.



That said, 11.5s - and 12.5s - offer more than just fragmentation range over 10.5s.

The OPs 11.5 chronos about 120 fps than most 11.5 bbls and the 10.3 is about 50 fps slower

No disrespect intended, but what if you are not going to the range?
What if you roll out of the gate with your weapon and that is all you have to work with all day?
Can you predict the maximum range at which you will have to engage threats on a given day?
Can you run back to base to get your 50 BMG from the toolbox if someone starts shooting at
you from more than 50m away?

eightring, absolutly..i hear you on that,.,, in real life though...what you are ''issued'' is what you have to work and maybe die with.
me personally... if that was the situation, id go like the USMC, and run a 20'' A4 with a 3x9 scope or ACOG.
can work in urban, and can get you out to 800.

call Chrony , maybe thier device is not calibrated properly ?
call Colt, because the 10.3 not 10.5 barrel is about 500 rounds young. and meticulously maintained.
that's what the chrony said it was. and that's only about a year old. fragmentation or not...hit ANY bad guy in the face,
( remember Zombies need head shots) and i think it will take them out of a fight. my buddy just got back from the shitbox,
and its not unheard of when a drugged up bad guy doesn't go down with a first round hit with any caliber. maybe 50
bmg might bring quiet a little quicker. even in Law Enforcement bad guys don't always go right down.

that's our information, if you want to debate it go buy your own uppers from 7- 24'' and a Chrony.
and we'll Gladly compare notes... and maybe learn more along the way.
this was about velocity, you other guys made it about frag. if your higly concerned you need fragmentation, get a 20''-24'' barrel.
and live happy ever after.

I have a Chrony and have used it with barrels from 7.5" to 20" including 10.5".

SO..........what kind of velocitys did you get ?? we'd like to know......

More or less in line with what Raizo_Sekai posted, which are from MSTN.





I also posted a link to velocity numbers from NSWC Crane that shows information quite different from your numbers (and also fairly close to what R_S reposted).





One thing to note is that with PMC, I saw up to a 400fps variation from the same barrel length. I tested this over multiple days to be sure.



 

Did you get to test out any 11.5s with xm193 or m855? I doubt a lot of 11.5s are as fast as the OPs 11.5. I'm wondering how much velocity do you lose going from 11.5 to 10.5

didn't davidc post the difference between 10 and 11.5 ?
i see that MSTN was slower the our 10.3'' ? i think for xm193.

we'll just do it again, feel free to send all ammo in five round increments to us, and we'll chrony whatever you guys want.
from 7''  to 24''. and any temperature. will post results.

there are always variables, humidity, different lots, etc. that is what we got...like it or not.
Also i seen much information about bullet drops , come ups out to 1000 yards for 308 and .260. and mine where never
exactly spot on as others... every gun is a little different.