Today’s post will focus on barrels for lightweight AR-15s.
People far wiser and with far more experience than me have said that a carbine’s balance is far more important than it’s overall weight. I tend to agree. More than anything, I like the idea of a carbine that is easy to point & swing, and that means a light weight muzzle. The easiest way to cut muzzle weight is by getting a lightweight barrel and handguard. However, there are practical limits to the weight of the barrel. We’re dealing with extremely high pressures here. Standard 223 Remington has a chamber pressure of about 50,000 PSI. It’s dangerous to have a barrel that is too thin.
A shorter barrel is lighter weight, but a carbine must have a barrel that is at least 16″ long under federal law (NFA 1934). You can build an AR-15 pistol, but that has other issues for another discussion. One way to shorten the barrel is to permanently attach a muzzle brake or flash hider to the barrel, but that causes problems with disassembling the rifle if anything is damaged. A lot of companies make “lightweight” barrels, but most of them don’t publish any details of the barrel profile. All we can do is compare them visually and search the internet for other people who have made comparisons. Some “lightweight” barrels really are not, but I forget which companies have a bad reputation for misrepresenting their barrels. If you’re seriously interested in building a carbine with a 14.5″ barrel, please go read this post: jerkingthetrigger.com/2014/01/23/14-5-barreled-uppers-maximizing-performance-and-your-options/
Mag Tactical Systems
Anyway, the lightweight barrel from Mag Tactical Systems seems to be an extremely thin profile. It appears that MTS was FAR more aggressive than most companies when they were designing their lightweight barrel. It looks like they cut every bit possible to create a true ‘pencil’ barrel. It should be noted that is uses a 0.625″ gas block and a midlength gas system. That’s generally a good thing, but the 0.625 gas block limits your options, but you were probably going to choose a lightweight gas block anyway. It’s also noteworthy to me that the MTS barrel is only $110, which is cheap for an AR-15 barrel. They claim the barrel weighs “1.2 pound” which would be a tiny bit over 19 ounces!!!
Update 2015: I have since learned that this is actually a Faxon barrel, and is about $30 cheaper from MTS than from Faxon. Also, I do believe that it is the lightest barrel that is commercially available.
Second is the lightweight barrel from VooDoo Innovations (which is connected to Adams Arms). While VooDoo barrels have a good reputation, but main reason I’m showing them is to illustrate the differences between barrel profiles. I used two pictures from their website, and put them side-by-side. You can clearly see the difference in how they’re cut. I think this is a good ‘baseline’ to compare with other barrels. www.voodooinnovations.com/barrels
And of course, I have to mention the V7 Systems barrel, just because it’s from V7 Systems. If you don’t know, V7 Systems is a company that specializes in ultra light weight parts for the AR-15. You’ll see more of their parts show up in future posts about ‘Project Featherweight’.
However, the V7 Systems barrel doesn’t even show it’s profile! Overall I’m not interested in the V7 barrels. Their 16″barrel costs $468! It comes with a titanium gas block pre-installed. It weighs 24.5 ounces with the gas block, and the gas block alone weighs 0.78 ounce, so we can deduce that the barrel itself must weigh 23.7 ounces, which is a full quarter-pound more than the barrel from Mag Tactical Systems! The fact that it comes with a gas block pre-installed means that if you were planning to use any other gas block, then you’ve basically wasted money on an expensive titanium gas block for nothing. I’ll explain later why I would *not* choose a titanium gas block for an ultralight carbine, especially if money doesn’t matter.
On the plus side, the V7 barrel uses polygonal rifling and a match grade chamber for better accuracy. This is one case where we need to determine what we want. If we want an affordable featherweight, the Mag Tactical barrel is a better choice. If we want a more accurate light-ish carbine with no price limit, then the V7 barrel is a better choice.
Of course, if you cannot find a barrel that you like, and you absolutely must have the perfect barrel, then you can get a custom barrel made or have ADCO modify any barrel you want (except those treated with hardening techniques like Melonite). However, you can expect to pay $120 just to have the barrel modified, not including shipping both ways, and the cost of the barrel.
Overall, I would personally choose the barrel from Mag Tactical Systems.