Expo Arms 10.3-inch Socom - Mil-Spec Features, Budget Price, Budget QC
Updated
40 months ago
Good morning, everyone, this is John with gun.deals, and today we're going to be taking a look at the Expo Arms 10.3-inch Socom barrel.
Full disclosure on the Expo Arms 10.3 barrel, this one here was sent out to us by Primary Arms, Expo Arms is Primary Arms in-house brand, so keep in mind that I did not pay for this. They sent me the10.3, the 11.5, and the 13.95, as well as their BCG as well, this is one of their hard chrome BCGs, as well as a couple handguards, one completed upper, so I have a bunch of their products to test out, so we're doing a basically full lineup review of the Expo Arms products.
Expo Arms is fairly budget and that is what's going to make them interesting, given their feature set, so this review is going to primarily focus on the barrel itself, but the handguard is also theirs as well as the BCG so we will talk about them just a little bit.
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Getting into the specifics on the barrel, it is a 10.3-inch carbine length barrel, so this is a 5.56, 1:7 twist. Very importantly on this one here, this is a Socom profile, which is like one step underneath a heavy barrel, it is, well it basically is a very heavy profiled barrel, which in theory will allow it to be very accurate, very rigid, keep in mind that this is a 10.3, so even though it is a very heavy barrel, it's still not too overly heavy as it is a short barrel but it is going to be a lot heavier than something like a government or even an M4 profile or any other profile out there other than a specific heavy barrel.
The material that Expo Arms is using is the mil-spec 4150 chrome-moly vanadium steel, which is a very tough, very durable steel. On top of that, this one here is chrome-lined and it has the appropriate frame spec .070 gas port size. I did check this with a pin gauge and it is the appropriate .070. I'm very familiar with this style of barrels, basically going to be exactly what you're going to find in a DD Mark 18, minus the Socom profile. Most of the DD Mark 18s are like a government profile, though it's a 10.3 so it's not quite exactly the same.
We're going to have some issues with this barrel because this barrel did have a couple problems in terms of quality control and manufacturing, but the feature set that we're going to go over is very good, unfortunately just wasn't executed all that well.
The main selling point behind this barrel are going to be the combination of its price, which is fairly low, and on top of that, also the very mil-spec feature set, and not mil-spec and kind of an arbitrary sense, meaning that it is the true mil-spec material, 4150 chrome-lined vanadium, they give the exact spec for that material, 10.3 carbine length phosphate chrome, so it is a chrome-lined barrel, proper crane-spec gas port .070, which will do very well with full power ammunition, if some of the other stuff on here were going well. It is also a dimpled barrel and can sometimes be found for like 99$ on sale, and that is a very hard feature set to get for around that hundred dollar price tag.
Getting into the issue that we had with this barrel is that, unfortunately the chrome lining in the chamber was not finished properly, there was something just off and I had to kind of hone it out, if you will. Basically, it was very difficult to get a picture of it, but there were basically like almost raised rigid or like some sharp edges inside of the chamber itself, meaning that for the first 10 rounds it would not extract a case and I would have to shove them out with a cleaning rod because they would get stuck in the chamber, they would feed alright but they would not extract whatsoever, so the extractor on their BCG would just rip off the side of the case and then it would not be able to be extracted because there were those burrs in the chamber that were holding those cases in there after they had fired because they expand a little bit, expand into those burrs and then the extractor just did not have enough force to rip them out.
The extractor on the BCG is all good, the fact is that the cases themselves were giving away, the case rim was bending out so that the extractor had nothing to grab onto so they had to be hit out with a cleaning rod.
Fortunately, I was able to solve that problem for the most part. Basically, what I did was hook up a copper wire brush to a drill and go to town on the chamber trying to clean it up a little bit and get those cases to feed and extract a little bit better. After about 10 to 15 minutes of work and on the next range trip I did confirm that I had fixed the issue of cases not being able to extract. Unfortunately, when you combine the very small gas port size, the crane-spec gas port size of 0.070 and the minor issues with the chamber, it was still very under gassed, even with full power M193. Basically, it's about 95% reliable with M193 and being very wet with lubrication, and in the back I am running a reduced power spring from Strike Industries. It wasn't a reduced power spring when I bought it, just over time has come that way and it has very little tension.
On top of that, we are running an aluminum buffer with no steel weights in it so it's an H0 buffer or a -1 buffer, if you will, because it does have no steel weights in it whatsoever, so I think it's like 1.3 ounces with a reduced power spring, and even wet with lube and with full power M193 it's about 95% reliable, most the time it will lock back, sometimes it won't lock back on the last round, sometimes it won't feed the next mag or the bolt won't quite get enough travel on it to feed the next round, so on and so forth, and that is going to be the main issue with this barrel.
Usually, with a .070 crane-spec gas port size, which is going to be basically the exact same as what is on my Mark 18, so it is the exact same barrel port or the gas port size. Usually what that means is that it will take full power M193 and a carbine buffer/carbine spring and it will run very, very smoothly. Unfortunately, there is still probably a little bit too much friction going on inside of the chamber that's slowing down the extraction, slowing down the bolt, and so you're not getting enough pressure.
On this one here it is a very simple fix for me and for the follow-up review on all of their products. I am going to open this up to like a 0.074, 0.076 and that should allow it to cycle just about anything at about 3 o'clock to3 30. If it was set up properly and the chamber did not have those issues, a .070 should function just fine with full power military ammunition and using a carbine buffer/carbine spring as it is we're using a reduced power spring and areduced weight buffer and it's still not perfectly reliable.
Hopefully, this is just a one-off issue, the rest of the Expo Arms barrels that I've tested do not have this issue, this was just something that was missed during quality checks, during test firing, if they did test fire the barrels they did not notice that whatsoever, so that is a bit of a letdown, but that is something that you need to be aware of when you're buying inexpensive equipment, sometimes you have to do your own QC, sometimes you got to do a little bit of finagling to get it to work properly, and this, unfortunately, is one of those cases.
If I had received a perfectly working barrel for that 99$ price tag I would be very happy with the performance out of it, unfortunately, it's one of those things that you really don't want to see that. I believe the OEM on these barrels is Rosco or at least Rosco is making some of the other Expo Arms products, though there could be multiple companies making Expo Arms products and then Primary Arms is rebranding them as Expo Arms, so I can't be 100% certain as to who the OEM is on this specific barrel.
Another issue that I have with this is that this is a heavy barrel, this is a Socom profile 10.3, so in theory it should provide you very good accuracy, that's going to be a trade-off, you get that weight but then you also hopefully get some accuracy out of it as well, and, unfortunately, this one here was not particularly accurate for us, it did about 4 MOA with just that ZSR M193 ball ammunition, which is not great, that ammo will definitely shoot at about 2 MOA out of a very high quality barrel and 3 MOA maybe on a mediocre barrel, this one here about 4 MOA, and then we also did shoot some 77 grain HSM, which usually shoots any bore between 1 and 1.5 MOA and, unfortunately, in this gun shot, about 3 MOA.
I'm sure if you were to test a wide variety of loads through it, it would find a load that did well. Unfortunately, in just a couple loads that I tested, that usually perform much better, did not perform particularly well in a barrel that is a very heavy barrel, so that is also a little bit of a downside. I personally am fine with heavy barrels, depending on the circumstance, as long as they provide you a high level of accuracy for that weight, unfortunately, this is very heavy with none of the benefits of being very heavy and since it's not hooked up to a machine gun, but I'm not putting four or 500 rounds through it in an hour, that weight isn't really helping you all that much in terms of like heat absorption and heat dissipation, so you're kind of getting none of the benefits of a heavy barrel, but all of the downsides of a heavy barrel, and on top of the fact that this one here had an issue with the chamber.
Me, being somebody who does testing an assembly for a living, this is a very easy fix for me to open up the gas port to .074., 076, somewhere in that range, to fix the chamber a little bit, that's all very easy for me to do, however, you, if you're trying to build your first upper or just trying to save some money on an upper, you like the feature set of the barrel on paper, you pick it up, I really don't want you to be going through and trying to troubleshoot a bunch of different issues to get your barrel that should work right out of box to actually function as intended.
I'm sure that most of the Expo Arms barrels are going to be perfectly fine, all the other ones that I have in-house, which I think is four or five at this point, have been just fine. This is the only one that I actually have a like manufacturing issue with or a quality control issue with, but that is going to happen more often on cheaper brands and this is a more budget in-house brand for Primary Arms. As it stands, I think if you get a barrel that is accurate and machined properly, you're going to be very happy with this performance, it's going to shoot very softly with that proper crane-spec gas port. This one here, however, is not particularly confidence inspiring, being that they sent me a bad barrel basically that does have some manufacturing issues.
