Editor’s Note: In this article, Dr. Will Dabbs evaluates the Speed-Tac AR Bolt Carrier in his Springfield Armory SAINT rifle. Designed for .223/5.56 and 300 BLK chambered AR-15 rifles, this bolt carrier is specially designed to improve the seating of a full magazine on a closed bolt. The bolt carrier was provided to the author by Speed-Tac for the purposes of this article.
The Speed-Tac AR bolt carrier represents an innovative solution to a timeless problem. While Gene Stoner’s AR-15 is generally recognized as the most efficient rifle design on Planet Earth, it is nonetheless still reliably difficult to seat a fully loaded magazine with the bolt closed. The lamentable reality is that if you ever try to slam in a loaded PMAG with the action closed, there will always be a little lingering doubt concerning as to whether that magazine actually locked in place or not.
If the magazine subsequently falls out during a recreational afternoon at the range, your fellow shooting buddies will just laugh at you. If that happens anywhere else, the end result could be much, much worse. The Speed-Tac AR bolt carrier is an inspired solution to that organic mechanical issue. This is one of those, “I wish I had thought of that”-sorts of inventions.
Analogies
In 1935, Malcom McLean lacked the money to go to college. He did, however, scrape up the cash to purchase a single used truck. This one vehicle formed the basis for the McLean Trucking Company.
Malcom McLean’s business model hinged on efficiency. Moving more cargo in less time minimized his costs and maximized his profits. Then, in 1956, he had an epiphany.
Across the world and even throughout World War II, cargo was meticulously loaded aboard oceangoing freighter ships by professional stevedores who played a huge game of Tetris with every load. This system was intrinsically slow and cumbersome. McLean therefore designed a standardized steel shipping container that could be packed with stuff and then stacked to fill the hold of a cargo ship both quickly and efficiently. In so doing, Malcom McLean legitimately changed the world.
By 1978, McLean owned a fleet of 4,400 container ships. His was the largest commercial fleet in the world at the time. His net worth eventually climbed to over $400 million. And those were 1980 dollars.
Malcom McLean globalized trade and subsequently changed the way the world worked because he looked at common problems and developed innovative solutions. Similarly, the good folks at Speed-Tac saw an issue intrinsic within the AR-15 rifle and engineered an innovative way to address it. The result is rugged, reliable, effective, and inspired.
The Crux of the Problem
There are basically two broad categories of magazines in modern sporting rifles. The AR-15 sort slam straight up into the magazine well and latch in place. By contrast, those of the Kalashnikov incorporate a small steel tab at the front of the box. To seat this sort, you hook that tab up front and then rock back on the magazine to engage the mag catch.
The appeal to the AR mag is that it only requires a single action. Just shove it up in there until it clicks. By contrast, that of the AK requires two separate maneuvers. That’s two opportunities for failure under pressure instead of just the one. That doesn’t seem like a big deal right up until it is.
The two-step AK magazine does have the additional benefit of mechanical advantage. Seating the box turns the mag into a lever that can easily lock in place even when completely full. By contrast, it takes a fair amount of intentionality to get a full AR mag secured in place with the bolt closed.
The Kalashnikov doesn’t have a last-round bolt hold open feature, so all AK mags are loaded with the bolt forward. In theory, your favorite AR is designed to be reloaded with the bolt locked to the rear. However, if you have a lull in competition or a real world engagement, it is always a good idea to top off with a fresh mag even if the chamber is still hot. That’s where the AR magazine conundrum arises.
The reason this is such a chore is that the bottom of the bolt carrier depresses the round stack slightly in an AR when a full mag is loaded with the bolt forward. This counterpressure not infrequently prevents the magazine from seating fully. In many cases, troops operating in the field will download their mags by a couple of rounds to make this easier. Now, however, thanks to Speed-Tac, there is an engineering solution to this nagging problem.
Gun Physics
We generally stratify modern sporting rifles by their operating systems. In general terms, such guns are mostly either direct gas impingement or gas piston-driven designs. Examples of the former would be the Springfield Armory SAINT. The latter would be the M1A. However, those distinctions are not really technically accurate.
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To the purist, both guns are piston-driven. It is simply that, in the case of the SAINT, the bolt carrier itself becomes the piston. The real distinction therefore becomes where exactly the gas is put to work. In the M1A, that is up front so the action runs cleaner. In the case of the SAINT, carbon fouling makes it into the receiver, so regular cleaning becomes more important.
In theory, the direct gas impingement design is both more accurate and simpler. Regardless, it is the AR bolt carrier that is the source of the mag seating issues. That is where Speed-Tac focused their efforts.
Details
The underside of the bolt carrier is where the real magic happens. That’s where the rifle interfaces with the round stack. The good folks at Speed-Tac cut up a bunch of old bolt carriers on a milling machine until they got the geometry right. The Speed-Tac bolt carrier is a drop-in fit for any milspec AR-15 rifle. It runs great in my SAINT.
The Speed-Tac carrier sports a carefully contoured underside, where the GI sort is just flat. This patented design retains plenty of material to ensure it remains structurally sound. However, they milled out the space that contacts the top of the magazine to provide relief for the first round in the mag no matter whether it is on the left or the right. The end result is that the fully-loaded magazine snaps into place with the bolt forward just as though it were locked to the rear. The difference between the Speed-Tac carrier and the GI sort is night and day.
Practical Tactical
I tried this carrier out in my Springfield Armory SAINT using both GI aluminum magazines as well as Magpul PMAGs. In both cases, the fully-loaded magazines lock in place quickly and painlessly. Giving the loaded mag a quick tug to make sure it is secure is always a good idea with any rifle. However, in my experience, the Speed-Tac carrier locked in nice and tight with minimal effort.
This carrier represents the state of the art. It sports a full-auto profile and does everything the GI component does only better. It is available is either silver or black finishes.
The silver version features NP3+ (Electroless Nickel/PTFE with a High Phosphorus Electroless Nickel undercoat) applied by Coating Technologies. PTFE stands for polytetrafluoroethylene. That’s Teflon in the vulgar tongue, and it is inimitably slippery.
The black variant is black nitride coated. This finish involves thermochemical surface hardening and offers enhanced lubricity when compared to smooth raw steel. Both finishes are harder than woodpecker lips. Just pick silver or black and go to town.
Both versions are cut from 8620 hardened steel with screws that are properly torqued and secured with Loctite. The gas keys are staked to milspec standards. The Speed-Tac carrier is a seamless substitution that runs .223, 5.56, and 300 BLK in any appropriate host rifle.
Ruminations
The patented Speed-Tac bolt carrier is an inspired solution to a mechanical quirk organic to the AR family of rifles. The issue it addresses is admittedly fairly narrow, but it does so brilliantly. There is ample up side and, as near as I could ascertain, no down. The silver version is available online for $159.95. The black nitride sort is thirty bucks cheaper.
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