I waited nearly 8 months for the stamp then I laid down $640 for a brand new in-the-sealed-box complete Colt Commando upper (11.5"). I slapped that baby on and took it to the range to check it. The lower is YHM. I think the FCG are Colt parts I had around (built the lower a while ago). I shot 40 rounds of IMI M193.



Grouping was low at 25 and 50 yards and I determined I would lower the front sight post when I got home, since the carry handle was bottomed out for that range. No failure to feed, no failure to extract. No problem.

I also noticed that the bolt would not hold open (sometimes) on an empty magazine. One magazine was an old Adventureline 20 rd., the other was an old Simmonds 20 rd. I decided the bolt catch was a little stiff, being all new and parkerized, and was rubbing with enough friction to be sticky. OK.

I got home and pulled the bolt to clean it and inspect everything, and what I found blows me away. The 5 o'clock and 7 o'clock ramps on the barrel extension are shaved away. After 40 rounds? I can't figure it out.



There is no evidence of peening on any of the bolt lugs, front or back.


I did find a flake of metal shaving resting on the ejector plunger. I don't know how much more shavings there were since I was cleaning the bolt face at the time.


The cases were apparently hitting the ejection port with a lot of force. All are dented in the same place and the brass deflector is clean. Buffer is H.


So ARFCOM, what in the hell happened? I see no evidence that the feed ramps were gouged by the bolt. Don't tell me it came from the factory in a sealed bag that way, because I'd get more livid than I am now.

Help.

EDIT: I checked the archives for an old thread of mine (15 years?). I think it was in the EE for a new stripped Colt upper where the M4 feed ramps were added to the receiver after it was originally manufactured. They were in the white (cut after parkerizing) and appeared well shaped. I recall that it was determined it was actually done by Colt and had been seen by others. If that is the case here for the barrel extension, it's quite the roto-rooter job for an unknown reason.

Those are OEM Colt dremel feed ramps.
Put H2 buffer in it

Colt loves to butcher the feed ramps before the send uppers/barrels out. It's absolutely ridiculous.

One would think that seeing a factory adjustment means it needed an adjustment. What in the hell could be so out of whack that it needed to be ground in two places? Hasn’t Colt mastered making M4 uppers and barrels yet?

Did the rifle preform as intended. You had no malfunctions other than the occasional failure to lock back on an empty mag. This could be due to a new parts in a new rifle to ammo to mags or a combination of all 3.

What's the problem?
A small amount of material was removed from a couple of places.
Whenever you start going beyond a rifle's design envelope, adjustments have to be made. You have a rifle with a really short barrel. It's going to need a few thing a rifle with a 21" bbl isn't going to need.

Haha Top. Tier.

I'm an engineer and I've designed and manufactured stuff. The problem is that Colt has chosen, for whatever reason, to do an imprecise manual manufacturing step for an unknown reason, and they are recognized as experts at manufacturing M4 (and other) carbines by the millions.

What about an 11.5" barrel pushes the design envelope for feeding rounds up that ramp that necessitated altering the structure? And if there is a valid reason, why not design the barrel extension for that case and avoid the extra manual step that looks like an afterthought by a guy who exposes his ass crack when he bends over to fix the refrigerator?

My upper works. Maybe it would have worked without the modification too. The fact that someone thought it wouldn't work (or work better) without the modification is the disturbing part.

This isn't an 11.5" or short barrel thing, it's a Colt thing. You'll find the same monkey Dremel marks on Colt 16", 14.5", and 10.3" barrel extensions as well. The last factory Colt 10.3" I bought brand new in the bag had them, as did the last 16" barrel on a complete 6920 - it's extremely common. Not sure anyone has a logical explanation of why they're doing it, but it won't affect function, so I wouldn't worry about it.

On the other hand, none of my DD 10.3" barrels have any such goofiness going on.

There's nothing wrong with it, except you're using a grossly underweight buffer. H1 minimum, preferably H2, and it might even run an H3. Also, do you know what recoil spring is in it? Not all recoil springs are created equal.

Regarding the polished feedramps, most manufacturers don't even bother to do it. That's one of the nice things about Colt is they take the time to do the little things that actually matter to the functioning of the rifle, vs. the cosmetic things other manufacturers spend money on. Barrel extensions come out of the machine with sharp corners that technically should be knocked down a little. Sharp feed ramps is actually a sign of good machining. The sharper they are the higher the quality usually. But they need to be knocked down for smooth feeding.

It's my first SBR and I pulled a new H1 and spring out of my stash so I could go to the range. I have been reading on buffer weights and I have an H2 on the way, but no different spring. I suppose that's my next lesson in tuning this rifle correctly.

I honestly don't know what spring comes standard with any given Colt rifle. I don't know if they're just standard carbine springs, enhanced, or whatnot. And I don't know if all Colts come with the same spring, or if they use different springs in their factory SBRs. Personally I think it's better to increase buffer weight before you start going after heavier springs, but it's no telling what you're starting with in this case. If it came out of a high quality rifle then it's probably good to go, but if it came in one of those value brand buffer kits then who knows.

My 2013 Colt SOCOM barrel has similar “machine” marks on the feedramps.

Lol... calling what Colt does "polishing" is an extremely generous euphemism; "grinding" is a little more accurate description. It's just sloppy half-assery that smacks of "field expedient" (I suppose, in this case, it'd be "factory expedient"). Somehow other manufacturers with current and past military contracts (such as Daniel Defense and FN) manage to produce fantastic barrels that are every bit the equal of Colt without resorting to any such shenanigans on their extensions.

Point of fact, I don't recall any such "special modifications" on Colt barrels a decade or more ago, so this seems to be a fairly recent "innovation" even for Colt. Maybe it's a response to aging machinery or something of that nature, but it's by no means a requirement inherent to producing quality barrels/extensions.

Don't get me wrong, it's functional and it'll work, but let's not try and put lipstick on a pig and pretend they're doing something extra special for us here. If there is a problem necessitating such modifications, I'd prefer Colt address it and put a leash on their Dremel loving shop monkey.

I really don't know what they were doing more than a decade ago, especially considering their gov and commercial lines were completely separate entities back then. But polishing is something that all ARs can benefit from, and it helps smooth out the feeding. There are no shenanigans. Just added value.

Just for funsies, let's compare the extensions on two brand new 10.3" barrels.



On the left is a Colt, with extra special "value-added" Dremel work. On the right is a Daniel Defense (FYI, this is what polishing actually looks like). Which would you prefer?

Mine doesn't look like that for one thing, so I can't really address that. Mine is even and symmetrical, as is any I've ever seen. Not sure what's up with that one.

Thing is, you're not actually polishing the feed ramps. It's those two little corners at the tops of the ramps that cause issues. If they're sharp enough, they can actually grab the bullet nose. Most people who talk about polishing their feed ramps are actually polishing the ramp portion where the bullet doesn't even get hung up and totally ignoring the corners at the top. I've pretty much figured out how to polish feed ramps, and Colt does it right. Like it or not, that's the fact of the matter. If you don't like it, don't buy a Colt I guess. I don't really know what else to tell you.

Are the DD feedramps fully polished? If so, I don’t like that any more than the Colt “polish” job. I prefer my feedramps to have phosphate on the steel.

The Colt 10.3" barrel above isn't even a particularly egregious example; I've seen far worse. My last 16" barrel was an example of "far worse," but I'm not sure I have any pictures of it. It was highly asymmetrical, sharp and rough (and wasn't remotely "polished").  It appeared to have been done either with a grinder or perhaps a cut-off wheel - similar to the first photo below.

The below photos also serve to illustrate the random, sloppy variation - Colt doesn't even have a uniform method they're employing. It ranges from halfway decent work to "Bubba plays gunsmith with the Dremel." In the second photo, the idiot actually nicked the chamber. Surely you're not suggesting that's "value-added," too ;p.





Here it's at least mostly uniform, but again, the method varies wildly:


Point is, while it's functional, it's hardly what I'd call optimal; not sure why you're so adamant about defending it. Suggesting that a manual method that's haphazardly performed (seemingly without consistent standards) and lacking uniform application is the best way to do it just doesn't make sense to me. If Colt were doing them all in a uniform manner, it'd be fine.

Yes, they're fully polished. As far as corrosion resistance, some portion of the barrel extension finish is going to be worn off and "polished" with use anyway. So, it's sort of a moot point - you're going to have bare metal to some degree eventually.  Personally, I prefer the thorough and uniform polish utilized by DD.

Just to be clear, I have no issue with polishing the barrel extension feed ramps. I want them polished - it's only going to increase feeding reliability and is a desirable feature IMO. I just take issue with the often sloppy and haphazard way in which Colt performs... whatever it is they're doing in some of the above pictures.

I’m not justifying Colt’s polish job in the least. It bothers me.

Re: bare steel after a lot of use, I have a couple barrels that have 10k rounds through them and they are not bare steel. It’s copper cladding impacting upon steel. The copper cladding is softer than the steel.

I’ve never seen one like that except for the photos people keep posting on this site. I don’t know what the story is on them, but I feel like there definitely has to be a story. Counterfeits, something the distributor cooked up, I have no idea. Only ones I’ve ever seen that I knew were Colt looked like they had been done on a machine. Perfectly symmetrical and smooth.

If I got that barrel you posted I would be sending that shit back to Colt in a big hurry and screaming bloody murder until they replaced it. I would certainly be very interested to know what they have to say about it.

Well, that's strange. My experience has been that the hack jobs are almost the norm rather than the exception; I'm so used to seeing it that I never even considered the above 10.3" out of the ordinary. As mentioned, it's actually a good deal better than the extension that was on a 6920 OEM I got earlier in the year. And I'm not the only one who has had direct experience with this particular issue and the barrels in question are definitely all legit Colt. That photo with the cuts into the chamber was/is a barrel belonging to MILSPEC556, so it's not just a random photo without a reliable source.

@Tigwelder1971
@MILSPEC556

Not sure the story behind all these Dremel hack jobs, but it's happening often enough that I don't think it can reasonably be called a fluke.

Why is no one returning these monsters to Colt?

If I got one of those it would be going back that very day. Idk, guess I've just been lucky or something.

My noveske made 10.5” was perfect for 12kish rounds, much of it suppressed.

This is a colt thing, not a sbr thing

I'm having a kanniption right now over the idea that someone could get a barrel like that and not demand that Colt replace it. How is Colt not being inundated with angry phone calls?

Exactly... I'm pretty sure most of the recent 10.3" batch had it to some degree or another (and from both sources). It's one of those things... it works, so it's really not worth the bother to get it replaced. That said, it sure could be done with a lot more uniformity and consistency.

On the other hand, all three of my DD 10.3s are absolutely flawless ;p.

ETA: When they vary from Ray Charles drunk with a Dremel to not touched at all, you really have to wonder what criteria (if any) they have for which barrels get the extra special treatment.

Attached File

New 11.5 FBI barrel from Shark Arms. 10/17 date on the barrel.

I’ve been saying for years now that the American gun industry is having a quality crisis across the board, and I always considered Colt to be one of the few exceptions.

Looks like maybe they caught whatever disease brought down the other guys.

Everyone who got these needs to hound Colt until they make it right. The last two Colts I bought were just fine, but both were originally destined to go to .gov customers.

Thanks for the discussion. I don't know whether to consider grinding the ramps to be a service or an oops-fix. It still seems to me that whatever is being tuned can be accounted for by design and then manufactured accordingly.

In the meantime, I installed an H2 buffer and the brass is still dinged upon ejection, but less so. I may go for an H3 and/or stiffer spring.

I just run H3s in all mine from 8.5" to 16" both 5.56 and 300blk. They all function fine. Basic carbine springs.

One exception. I made one which is between H2 / 3 weight.

I have a Colt Commando barrel (the real 6933 lightweight barrel) that I got for my FBI upper build, and the gas port measured .074" using pin gauges after I yanked the FSB.  I put an .067" BRT gas port reduction plug in the gas block I installed on it.

And yes, the Colt Dremel Monkey had his way with that barrel.  It works fine.

Curiosity got me so I checked my Colt 6920 Trooper (16"). Purchased new around Oct 2017. Ramps, etc appear unscathed and normal to me. Long thread so I'll just ask the question first. Within Colt is this anomaly limited to shorter-barreled guns? Thanks.

Companies only get away with these shenanigans because people put up with it.

The last 6920 I got has it, but luckily mine were extremely well done.

Sample size of one so take it with the appropriate grain of salt, but a good friend of mine has a 14.5 socom bbl with the same bubba'd feedramps. I'll ask him when he purchased it but don't believe it's a particularly old barrel.

That's true in general terms, but I'd bet dollars to dimes that Colt wouldn't care about complaints unless they reached a massive, critical mass. Their economy of scale is huge courtesy of contracts and market share.

500 ARFcomers could call and complain over the course of a month, it would be a drop in the ocean for them. The vast majority of their clients aren't going to notice or care.

I don’t know it seems like an awful lot of people are noticing and it seems like they care very much.

So many choices out there in 2019 (better choices) why even buy colt anymore.

ETA - not being a smartass, just sayin

For the record and thread posterity, I switched to an H3 buffer and a stiff buffer spring from Wolfe. That very nearly cured the problem of dinged brass. Dings are a lot lighter when they happen, and often times it doesn't happen at all.

I'm amazed at how much this system needed to be slowed down to accomplish that.

In a 11.5” barrel, things happen really really fast.