Rob_s' "The Chart": updated!!!!
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Rob_s' "The Chart": updated!!!!

This is a discussion on Rob_s' "The Chart": updated!!!! within the Rifles forums, part of the Gun Forums category; Per the authors request, rather than linking directly to the Google Docs spreadsheet, I am linking to the relevant thread on a different forum: NEW ...

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  1. #1
    00000 kartoffel's Avatar
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    Rob_s' "The Chart": updated!!!!

    Per the authors request, rather than linking directly to the Google Docs spreadsheet, I am linking to the relevant thread on a different forum:

    NEW Comparison Chart of Commercial M4 Pattern Carbines - M4Carbine.net Forums

  2. #2
    Negative Nancy einzelherz's Avatar
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    There are a lot of things wrong with that chart

  3. #3
    00000 kartoffel's Avatar
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    Like what? I am genuinely interested in your knowledge, Einz!

    Personally, here's my wish list for the new chart as it evolves:
    - barrel gas port diameter
    - barrel nut assembly (did they use anti-seize or what? did they snug it 3 times, torque to XX ft-lbs, and then advance to the next notch, or what?)
    - bolt and carrier surface treatment (parked, nitrocarburized, WDLC, hard chrome....)
    - whose trigger assembly is in it?
    - all the springs: are they spring steel, chrome silicon, mystery metal...?

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  6. #4
    Negative Nancy einzelherz's Avatar
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    Well based on the material alone, there's only one bolt out of that group I'd buy.

    Shotpeening the bolt doesn't do anything on an AR because the lugs are too small for effective sized shot to actually peen. Having the shot peen method on there just makes it more hilarious.

    The coil count (I assume) on the extractor spring is funny because they're all probably the same spring, but the coils are counted differently.

    Not even sure what a shrouded carrier is. That's a new term for me.

    "11595E" means 4150 or a vanadium alloyed version of 4150. I'd be more interested in what the barrel blank's manufacture type it is. FWIW they're most likely forged, which means they're hopefully Colt blanks.

    There are better things to treat a bore than chrome lining so having this as a binary column is kind of pointless.

    I've never seen an upper that had its M4 feed ramps cut after anodizing. That might be the stupidest thing I've ever heard (assuming it happens)

    No idea what "FSB - Full" means. I assume it's full length, as opposed to a ~1" low profile length.

    To answer your questions kart,

    Gas port diameter shouldn't be listed. IMO it gives too much info to the customer. As far as business is concerned; you say it's .082 and some idiot gage pins it to .083. He then calls your customer service demanding a replacement barrel because he doesn't understand how tolerance works. OR you have such a hard time getting your guns to run consistently you have to open ports up on the more poorly functioning rifles.

    I've never used antiseize on any barrel nuts I've installed. I've never snugged it three times (I don't quite understand the point of this.) Per the military specification there is a large torque range. If when tightening on the nut to align it the torque is outside that range, you get another nut. Torque to XX and then advance will never achieve consistency.

    Bolt + carrier: I can agree with you on wanting to know these things. I don't know what WDLC is though.

    I assume all of them have a standard garbage milspec trigger from whoever they could get it from for the least money. This isn't something they're going to tell you.

    As for springs, I'd be willing to bet that half the manufacturers don't know what material they are. A lot of the smaller springs come from one or two companies (DPMS is one of them.) The buffer spring is the only spring I know of that is ever significantly different, and ironically it's the only spring in the gun that's not significantly overstressed (if at all.)

  7. #5
    00000 kartoffel's Avatar
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    Quote Originally Posted by einzelherz View Post
    Shotpeening the bolt doesn't do anything on an AR because the lugs are too small for effective sized shot to actually peen. Having the shot peen method on there just makes it more hilarious.
    You know, that is an excellent observation.

    Quote Originally Posted by einzelherz View Post
    Not even sure what a shrouded carrier is. That's a new term for me.
    I think by "shrouded" he's referring to the old Colt half-moon carriers. They had a cut that extended all the way to the very back, leaving it C shaped instead of O. The cutout was meant to clear some kind of sear blocking doohickey that Colt used to stick in their ban era guns. No idea why this is relevant, as nobody but Colt ever made halfmoon bolt carriers, and aside from being a hair lighter than standard there's nothing wrong with them.

    Quote Originally Posted by einzelherz View Post
    "11595E" means 4150 or a vanadium alloyed version of 4150. I'd be more interested in what the barrel blank's manufacture type it is. FWIW they're most likely forged, which means they're hopefully Colt blanks.
    AFAIK, Colt and Daniel Defense both hammer forge barrels in house. BCM, LMT and possibly others also use hammer forged barrels, but may or may not be members of SOPWAMTOS*

    Quote Originally Posted by einzelherz View Post
    There are better things to treat a bore than chrome lining so having this as a binary column is kind of pointless.
    Well.... that's rather contentious. There was a shitstorm on M4C last week on Melonite vs. Hard Chrome. Half the people confused hard chrome with shiny bumper chrome plating, and the other half dissed S&W for cost-saving choices unrelated to their Melonited barrels. What remains, however, is the difference between the surface hardness and cold wear resistance of nitrocarburizing vs. hard chrome, and the throat erosion resistance at high temperature.

    Quote Originally Posted by einzelherz View Post
    I've never seen an upper that had its M4 feed ramps cut after anodizing. That might be the stupidest thing I've ever heard (assuming it happens)
    DPMS was guilty of this, as well as various internet Dremel commandos who posted their monstrosities on ARFCOM.

    Quote Originally Posted by einzelherz View Post
    No idea what "FSB - Full" means. I assume it's full length, as opposed to a ~1" low profile length.
    The F is for flat top. FSB's for old carry handle weapons are 20 thou shorter, for whatever reason. If you use one on a flat top gun and "machine zero" the front sight post with the flange flush with the top of the sight block, it'll shoot high. Bushmaster (among others) solved this minor quibble bass-ackwardly by making sight posts that are 0.020" taller than normal. Whatever. There's enough adjustment in the threads to compensate either way... it just annoys armorers who machine zero a whole rack full of weapons and expect them to at least be on paper based on setting them that way. Alternatively, bitches could learn to zero their weapons.

    To differentiate between short and tall FSB's, Colt took to stamping the taller ones F, for flat-top. Other manufacturers (LMT, for instance) were more confident in not getting their parts bins mixed up and never bothered with a gay stamp on the FSB, but for whatever reason the Tier One crowd insists on having an F on their M4 front sight blocks. I stamped a K on my LMT block, just to pre-emptively fuck with the first person to look that closely. Nobody seems to care. Yet this column exists on The Chart.

    Quote Originally Posted by einzelherz View Post
    Gas port diameter shouldn't be listed. IMO it gives too much info to the customer. As far as business is concerned; you say it's .082 and some idiot gage pins it to .083. He then calls your customer service demanding a replacement barrel because he doesn't understand how tolerance works.
    Well, if an armorer knows a batch of weapons is coming with a larger gas port, they can pre-emptively drop a heavier buffer in them before sending them out. I bet you'd also see a strong relation between buffer weight and port size from all the manufacturers on The Chart. There's also a tendency for the "shit tier" guns to be overgassed, but this seems to be a proactive choice by those manufacturers who (a) realize their guns may be rougher than most and (b) will be fired mostly with low pressure .223.

    Good point about idiots measuring them and bitching, too... but you assume an idiot would actually properly use a gage pin rather than just eyeball it with calipers

    Quote Originally Posted by einzelherz View Post
    I've never used antiseize on any barrel nuts I've installed. I've never snugged it three times (I don't quite understand the point of this.) Per the military specification there is a large torque range. If when tightening on the nut to align it the torque is outside that range, you get another nut. Torque to XX and then advance will never achieve consistency.
    This is another point from the armorers. Rebarreling guns assembled dry is a total bitch. To get the torque repeatable and consistent on every gun you put together, the "3 snugs" method works wonders. It's supposed to wear and mate the threads, so the final torque more closely corresponds to the true axial load. The final torque is not something you can pinpoint, because a notch on the barrel nut has to align for the gas tube to pass through. Yes, you can time it with shims, but again this is not something that armorers prefer to do.

    WDLC is tungsten (W) diamond-like coating. It's a relatively low temp vapor deposition process that can be done to bolts post heat treat. Other non-parkerizing options would include hard chrome, nickel teflon, boron carbide, and so on.


    * Society of People Who Actually Manufacture Their Own Shit, an old mountain biking in-joke. Basically, small manufacturers were frustrated that so many Gucci parts were assembled from outsourced components. All the cool kids roll their own machine screws in-house. It's a total bicycling faux pas to show up with a $300 CNC'ed brake caliper sporting commodity grade YFS machine screws, don't ya know.
    Last edited by kartoffel; 06-29-2011 at 09:48 PM.

  8. #6
    Negative Nancy einzelherz's Avatar
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    The chrome vs melonite is contentious. However, I've done/seen the testing that shows throat, bore, and gas port erosion is much worse on chrome when compared side by side with melonite. There is a caveat that I had forgotten to mention; chrome has a thickness whereas melonite does not. What this means is that if your bore is meant for chroming (i.e. oversized) then melonite won't give you as good of a gas seal. This is a problem because every hammer forged barrel I've ever seen was made with the intent to chrome. One would have to find a barrel maker than hammer forges stainless barrels in order for the best (imo) combination of hammer forged + melonite.

    The heavier buffers do not significantly slow the gun down enough to compensate for gas port differences. The 20g difference between a steel and tungsten buffer weight is minuscule.

    Torquing three times might work in the case of a barrel nut (where you have a large range) but doing so when you're seeking to hit an actual torque value is bad. Each time you snug it down again, you're actually increasing the overall torque value, albeit by a very small amount. I've rebarreled guns after them being assembled dry, but they did not use the M16 barrel nut. I've only dealt with that particular turd a few times

    I had forgotten that DD forged their own barrels too.

    It also occurred to me after posting that this appears to be a strictly M4 thing, which for me, is meaningless. If I bought an AR, it wouldn't be a COTS M4 clone.

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