i cant remember if we talked about this a hundred pages ago, but for those of you with the socom barrels is there any NOTICEABLE accuracy difference? also, a socom isnt horribly needed is it? i mean, i cant imagine every m4 has been rebarreled with a socom barrel.

Actually, that would be my Trifecta/Family Pic thread

I haven't had to deal with the pinning stuff, so I don't know about that.

Haha.  I posted in there.  Ill do my part to get it off the ground.

Never even saw that one. I'll post in it when mine are ready :)

I spy with my little eye... an MRDS with hood!

"Horribly needed," not in the least bit.  

Accuracy is not particularly the issue, and never was - in military service, it's an overheating issue.

I personally prefer the HB-profile simply because it balances well, and has less hypothetical deflection when mounting a suppressor.  While in a practical sense, it will more than likely have neither a significant effect on POI shift, nor will I likely ever get a government profile barrel hot enough to induce a catastrophic failure of the barrel, I simply feel that the medium contour, gently tapered barrel is a far more sensible profile than government profile barrel.  It distributes heat more evenly, and takes longer to heat up.  

I also prefer my "fighting" guns somewhat front-heavy, as I feel that it helps with perceived recoil.  

All in all, though, I would call it a relative non-issue, and my preference for the HB-profile in only a minor matter of degrees - I own multiple government, and HB profile M4 barrels, and don't concern myself terribly over the differences between them.  

That being said, in terms of military weapons:

The vast majority, that is to say, the only exceptions might be a couple of pockets of support personnel or backup weapons in the back of an arms room, of military M4A1s are equipped with the RO921HB profile barrel, including those that were originally shipped with the standard barrel.  Understand the change was made around 2000, and all M4A1s produced for the government since then have been HB-profile.

Furthermore, current plans, in the Army at least, are to upgrade and/or replace M4 Carbines in conventional unit service with PIP M4A1s - with a major component of the conversion being re-barreling with the RO921HB barrel.  The M4A1 PIP (RO921HB) would supersede the M4 (RO920) as Standard A.  Then again, with upcoming budget cuts, who knows if this will actually happen, or if we'll go into the next war with the same twenty year old RO920s we went to the last one with.    

Not sure what Colt will do, or how they will respond if and when all contracts convert to RO921HB profile barrels - they may simply discontinue the government profile barrel altogether on the RO977, LE6921, and perhaps even LE6920 series in favor of HB-profiles.  

~Augee

why cant someone just offer a 14.5" socom barrelled upper with RIS II?! fuck. im trying to look around at getting the individual parts but between that and figuring out which way is cheaper and whether to get colt stuff or whatever brand and oh my god brain meltdown.

There were a few M4A1 RIS IIs on gunbroker for $350 as of lst night.

Why are you bent on a SOCOM barrel?  I love my mid-length. [shrugs]



 

It is somewhat odd though, that BCM sells all the components, but utterly refuses to combine them (during calmer times, I mean, I can understand their current reluctance to cater to "non-catalog" requests).  It's not, in my estimation, exactly an esoteric request.  

There's not even an option to buy their SOCOM upper without an FSB, and simply assemble it yourself that I'm aware of.  

They even go so far as to offer the RIS II FSP with an M4 barrel and even recently rolled out a 16" carbine SFW (CQFTHB) upper, but refuse to build "standard" Block II M4A1 uppers.  

~Augee

This Elcan kicks ass. Glad I finally picked one up.

That thing is a goddamn Block 1.5 specimen.

 

Spray paint that sucker before anyone finds out that it's black!

Haha yeah it'll probably get painted eventually. I sort of wanted a brown one but I don't really care one way or another. I got a pretty good deal on this one.

i dig the CAR stock!

& yes Elcan's glass is better than my own 2 eyes!

I'm a big CAR stock fan. I waffle back and forth between it and the SOPMOD, but for whatever reason I seem to always come back to the CAR. It just fits me right I guess. And I appreciate its simplicity.

This biggest "upgrade" from gov't profile to SOCOM profile M4 barrel, is that the SOCOM barrel can handle heat better.

There is a video somewhere, where I think Colt did a fuck ton of mag dumps in a full auto M4, one with a gov't profile barrel and another with a SOCOM barrel.

The Gov't profiled barrel ended up bending drastically at the M203 notch, while the SOCOM barrel became a semi-auto gun, then caught on fire, and finally blew up and fired a lot more rounds than the M4 with the gov't profile barrel.


I don't have that much ammo, or an M16...so I'm fine with a gov't profile barrel.

The CAR stock is pretty damn cool; USP45Tim just sold me one for $20 (thanks buddy, we'll settle up ASAP ).  I only wish there was a good way to attach a sling-socket to it.



 

what barrel brands are you all using?

i really want to try and build this upper with all colt parts (minus the FH), and with a KAC block. ill probably pass on the KAC block since its so expensive and go with either a DD or badger.

I used a BCM mid-length with a DD Mk12 manifold.  I find it a bit when you say you wanna build this thing with ALL Colt parts but will pass on the KAC gas manifold because of cost.  Colt is overpriced as fuck.  Hell, it's ALL overpriced in this climate.



 

i cant justify a $108 gas block i figure i can price hunt a bit. the assembled colt uppers are what is drastically overpriced, and i found a site that has complete colt uppers for 160 (at least i THINK the site is updated)

Give up the goods! That said, I bought a complete 6920 with the "M4 Carbine" roll mark so I could have one completely made from Colt parts. I ended up just cutting down the FSP, and like the results.

ETA, I also have a SOCOM barrel that I plan on putting on my SBR'ed lower, but am considering SBR'ing my 6920 as well to put it on that one.

No no, the gas manifold is justifiable.  It's those fucking micro flips that are practically IMPOSSIBLE to justify.





 

the KACs are the ones used on the real ones right?

and yeah i thought about getting a 6920 upper, but like i said those prices are crazy now but i think i can find the individual parts easier and for cheaper all together

What length barrel is that?

Got some much needed range time today Shooting factory loaded 5.56 in this current market, call me crazy. Range was empty with most of the shooters being mostly LEO.


Conditions: Foggy


Started off by confirming zero of the EOtech EXPS3-0 by shooting from the bench, that went smoothly and only minor adjustments were needed. Rest of the shooting was done standing, rice paddy prone, kneeling - averaged 6 inch groups at a 100 with a mixture of 60 grain FMJ and some left over 77 grain OTM. Good day.


The SF3P-556 works as advertised, no ping

You're a crazy SOB, p_m.

Yes, the SOCOM barrel is noticeably more accurate than a government profile barrel.  There is an extensive thread and test results on this very issue on the other site.

So expensive yet the Block II looks almost incomplete without them.

If you're referring to Front sights, yes, the KAC is stupidly expensive. As for gas blocks, DD, Badger and I think KAC are all appropriate.

They most definitely are too expensive but no other flips on the market look that sleek and low-profile.  Also, I used the DD manifold on my Block II and the Badger on my Mk12 Mod1.



 

Lol. That was the reaction I got at the range last weekend.

I fired off about 500 rounds of factory PMC Bronze, and a few guys walked up to me all like "what the hell are you doing man?"

Well, I'm about to go in on a new Dillon press with a good buddy soon so hopefully I soon won't have to regret the 1.2k factory rounds I've shot this month so far.

i was referring to the KAC gas block

Real ones used on the Block II's are DD.

oh, for some reason i thought it was KAC

Hey fellas.  I am thinking of moving my Eotech 553. Ill give the clone guys first shot at it.  Pm if you are interested.

13.5 barrel .Putting together a GL/SSC looking clone using a Ris II.

http://www.thefirearmblog.com/blog/2010/02/02/m4-carbine-torture-test/

To clarify - the government profile barrel ruptures, like the ones in the '96 testing - at the most narrow part of the barrel, just behind the FSB, where it "flares" to meet the FSB journal, the proverbial "Achilles heel" of the government profile barrel design.  The same testing also concluded that the M16A2/A3/A4 barrel was just as likely, if not slightly more, to rupture at the same threshold, which was counter to what their original supposition was - that the M4 would be less resistant than the M16.  

While the M203 notch could be considered a potential weak point in the barrel - testing would seem to indicate that it is not an issue at all - particularly compared to the profile under the handguards.

When the test was repeated with an RO921HB barrel, the weapon fired 911 rounds continuously, before the gas tube melted and ruptured, but the weapon could still be fired as a "straight pull" bolt action.  

I really wish that someone would run this same test on a lightweight M16A1 profile barrel, to see what the threshold of failure is compared to the government profile barrel - as I wonder how much dissimilar heating and cooling rates near the gas port (the narrow portion would heat up much faster than the .750 barrel journal), and excessive weight at the end of a "droopy" government profile barrel has to do with the threshold of catastrophic failure.  

While I do not ever expect to expend the volume of rounds in the short duration needed to burst a government profile barrel - what I begin to wonder is how much that dissimilar heating and cooling rate in such a short area affects the metallurgy of the barrel itself.  Though most people may not get the barrel so hot that it bursts, many fire a lot of rounds in short strings, getting their barrels pretty hot.  How, then, if under the handguards the barrel cools much faster than forward of the FSB, how does this affect the overall integrity of the barrel?

I can say for certain, because I haven't tested it, nor do I know enough about the physics behind it to make the call - but to me, it seems to make sense - and tends to make me feel that overall - while not necessarily immediately apparent - the RO921HB is preferable for weapons that will get relatively hot during their service life.  

Again, as I said, I don't make a huge distinction between the two, that is to say, I don't scoff at government profile barrels, and insist on only buying RO921HB barrels - but generally speaking - while I like government profile barrels for lighter weight weapons (I think the RO723 and RO727 are possibly the perfect configurations for a "no frills" carbine) that are carried more and fired less, for weapons that I intend to put a significant number of rounds downrange with, I try to stick with RO921HBs when possible.  

~Augee

I used the DDmk12 which is what crane accepted. I picked one up for 65.00 before they went out of stock everywhere. I think there is a company maybe it's badger that sells a copy of the design.

I shot off a round of M193 yesterday and immediately thought "damn, there goes a dollar".

Got my Block II put together recently
Parts List:
Lower
Mega stripped forged lower
RRA parts kit
Magpul CTR(what I had)
Upper
BCM stripped upper
BCM 16" barrel
BCM gas block
DD M4A1 RIS II FDE rail
KAC QD FH
KAC taupe front sight
FDE Magpul MBUS(what I had)

I am planning on getting a sopmod stock and KAC 300m rear sight. I also have the CQD rear sling attachment incoming and going to pick up the front one as well to attatch a LBT 2500BZ sling. Pics coming tonight or tomorrow when I get some time off of work

One of the MARSOC guys from Level Zero Heroes was running the 2.5-10x24 with an offset T1.

http://www.youtube.com/watch?v=UNNg5V8OfDk

No problem. Did it arrive?

has anyone used the new surefire 3 prong vs the 215A?

i still think i want to go with the 212 though because it adds less OAL

Biggest difference between the 215A and 3 Prong SF3P is the lack of the dull ping on the SF3P, keep in mind the ping on the 215A was not a problem at all and at most is a tiny, tiny dull ping. Not even noticeable unless you really try to listen for it.

212 looks pretty good too but I find that the prongs look bomber and flash suppression is better.

What sling/sling attachments are you guys using?

I use the VCAS sling and as far as attachment points I use the IWC 45degree offset qd point and the qd point on my SOPMOD.