A technological and marketing term called feature creep has troubled me for some time when it comes to service grade firearms. The term refers to firearms being loaded with add-on features that are not really needed for the job. Adjustable sights and target-type triggers on the 1911 handgun, and extended controls and light triggers on service grade AR rifles are among these features.
Feature creep makes the firearm incrementally more complex until the original intent is obscured. A real impediment is a designer that thinks his firearm must do everything and anything. I am not an operator, and I have not been on the front line in institutional service in some time. But I know what is needed in personal defense, service use, and in a good general-purpose rifle that will serve many roles well. Treading through a high density of egos, I find that a general consensus of what is needed in a service grade rifle would give us a rifle similar to the SIG M400.
Several companies, originally founded to manufacture handguns, eventually offered AR-15 rifles. Colt, FN, Ruger, and Springfield are among them. You don’t need the most expensive rifle, but you need a very good one.
SIG M400 TREAD
SIG’s M400 TREAD is among the most attractive rifles based on function and price point. The TREAD sells for less than $1,000 and offers reliability and performance. The name TREAD, by the way, is a play on the original American slogan Don’t Tread On Me. Since the TREAD is manufactured in the Granite State, home of Daniel Webster, this is a fitting name.
The rifle begins with the kind of barrel I would choose if building an AR-15. The stainless steel barrel is 16 inches with a 5.56mm NATO chamber, 1:8-inch twist, mid-length gas system, and a sturdily pinned gas block. This is the system I would choose for reliability.
The 5.56mm chamber is slightly less tight than a .223 Remington. If you handload, and use high-pressure loads, there is an advantage. The barrel choice dictates the weight of your rifle. The 16-inch light contour barrel is ideal for most uses. The barrel features a three-prong flash higher. It looks cool and seems to do the business.
The rifle comes standard with a 15-inch aluminum handguard that houses the free-floating barrel. That is a good gripping surface and offers plenty of real estate for mounting combat lights or lasers. The weight of the rifle, unloaded, is six pounds and eleven ounces.
There are two things that ensure AR-15 reliability. One of these is a gas block pinned in place rather than screwed in place. The other is a bolt with the gas keys staked in place properly. I still see mistakes, and all are not home-built rifles. Some of the factory units are ‘economy rifles.’
The TREAD is properly set up for reliability. The handguard is long enough for good purchase and mounting lights, with M-Lok slots spaced on the forward section of the handguard. The stock is the usual six-position adjustable stock — this one by Magpul. The upper and lower receiver fit well together with minimal play.
The rifle features an ambidextrous safety. The magazine release is also ambidextrous. A good touch is a tension device just below the receiver pin that may be used to tighten the fit between upper and lower receivers.
The trigger is — according to SIG — a single stage, and it is nicely polished. The trigger action breaks cleanly at six pounds and fourteen ounces of compression. The handgrip felt good as I tested the trigger, with plenty of gripping surface and a good fit for most hand sizes. The rifle is provided with one magazine. Like most of you, I have a box of PMAG magazines, and these were used for the test program.
When I picked the rifle up from my FFL, I decided to mount a SIG Romeo red dot sight. My friend John decided I didn’t have to spend a ton to have a good red dot on the TREAD. By the same token, we agreed that I should not go too cheap.
This rifle didn’t come and go as a test piece. I kept the rifle and it is on the front line. I have used a good dozen or so of SIG’s Romeo red dot sights and always with good results. So, a good sight was appropriate for a rifle that was going to be a keeper.
The exact version I chose is the SIG Romeo 5XDR. This a 1x20mm red dot. The dot has eight standard illumination settings. For bright light, a larger more visible dot is my choice. The red dot may be quickly adjusted down for dim light. Battery life is 50,000 hours — a huge advantage for those of us using several different rifles and dots, and perhaps not keeping as close a watch on battery life as we should.
A good rule of thumb, change the battery on your birthday. The dot is 1 MOA, and we have a total travel of 100 MOA for windage. The same generous spread is available for elevation. At 5.6 ounces, the Romeo 5 adds but little to the weight of the rifle.
Firing the rifle was accomplished with a good supply of ammunition including Federal 62-grain Green Tip, Hornady 55-grain FMJ practice ammunition, Remington 55-grain FMJ, and Hornady 55-grain V-Max. I sighted the rifle in at 25 yards. This was accomplished handily with a minimum of ammunition expanded.
SIG 400 TREAD Specs
Caliber: 5.56 NATO
Weight: 6 pounds, 9 ounces
Overall length: 32.5 inches (stock collapsed); 35.75 inches (stock fully extended)
Receiver: Forged aluminum
Barrel: 16-inch stainless steel, mid-length gas system, 1/8-inch twist
Muzzle Device: SIG 3-prong flash hider
Stock: Magpul SL-K
Pistol Grip: SIG
Forend: SIG 15-inch M-Lok
Trigger: 7 pounds specified, lighter as tested
Sights: None delivered
Accessories: One 30-round magazine
The rifle handled well in fast, reactive drills as I engaged man-sized targets at 15 and 25 yards. The SIG Romeo red is fast on target with good features making it an effective combat sight. The rifle handles well with a good balance. I leaned against the bole of a tree and took aim at a 50-yard target.
Firing quickly from this brace, I executed several double-taps. The shots were close together, and after firing five double taps, the X-ring had suffered. Settling down to a solid benchrest firing position, I fired the rifle at 50 yards.
Firing 3-shot groups, the Federal 62-grain and Hornady 55-grain V-Max tied for top accuracy — just under an inch for three shots. At 100 yards, I fired two 3-shot groups with each load. At this range, the best single effort was 1.5 inches, the average 2.0 inches — good for a red dot equipped AR-15.
At this point my experience is good but not very in depth. I would expect better results with a bit of exploration into ammunition and more acclimation as well. Just the same, I cannot fault accuracy results in any way. The SIG M400 TREAD never failed to feed, chamber, fire, or eject. The rifle is well made of good material and offers SIG quality at a fair price. It should be on anyone’s short list for a front line AR-15 rifle.