SIG M400 Rifle

Fast handling and reliable this is a great all around rifle.

My philosophy concerning rifles is to own but a few and master these rifles as thoroughly as possible. A primary rifle and a spare are good to have. The rifle should be light enough for constant carry, reliable, accurate enough for the task at hand, and simple enough for easy maintenance.  I am not an operator and I have not been on the front line in institutional service in some time. I owned very good rifles when I was in service and teaching carbine classes. One of my abstracts on a federal level has been extensively used in training and to convince city fathers to approve carbine deployment. The rifles I own today are better than anything in the past. As for an all around personal defense rifle the SIG M400 is as good as it gets for the price. There are cheaper rifles. They may be ok for recreational use but I have seen quite a few failures in the economy class. I can live without a lot of cheap rifles.

SIG’s M400 TREAD is simple enough- a very good AR 15. The rifle features a reliable trigger an M LOK forend and a ell designed grip. The gas block is properly attached and the carrier keys are staked in place as they should be. TREAD as the M400 is also called simply means don’t tread on me as American an expression as there is. Since the rifle is manufactured in New Hampshire the M400 TREAD is well named. The barrel is a stainless steel light contour 16 inch tube with a 1 in 8 barrel twist. A three prong flash hider is attached. The weight of the barrel sets the weight of the rifle and the light contour keeps the piece light. The gas system is mid length. The chamber is 5.56mm NATO well suited to any commercial ammunition. The TREAD features a 15 inch aluminum handguard housing the free floating barrel. If desired you have plenty of area for mounting lights or lasers. The stock is the usual six point adjustable length type. Unloaded the rifle tips the scales at six pounds eleven ounces.

The things that make the AR run correctly have been attended to. The gas block and carrier keys are properly set up. The trigger system is reliable and properly fitted. The upper and lower receiver fit well together with minimal play. The rifle features an ambidextrous safety and magazine release. The single state trigger was operated in dry fire a few dozen repetitions before range work. Trigger compression is a clean  six pounds and fourteen ounces. The rifle is provided with one magazine. The M400 worked reliably with a mix of Colt, OK, Brownells and PMAG magazines.

For optics I chose the SIG Romeo 5XDR. This red dot sight isn’t the most expensive but it offers good clarity and works well in fast reactive drills. The Romeo 5XDR was easily sight in. With a long lived battery life of 50,000 hours guaranteed I still change the battery on my birthday. The dot I 1 MOA with total adjustment of 100 MOA. The Romeo red dot weighs only 5.6 ounces.

Initially I sighted the rifle for 25 yards, getting preliminary zero out of the way. Sighting for 50 and then 100 yard was simple enough using the MTM K zone shooting rest. I used some of the last o a long hoarded supply of Black hills ammunition 55 grain FMJ loads. As I near the last few boxes of this loading ammunition availability is much better in both price and quantity. I enjoyed firing tis combination off hand from barricade and prone behind cover. At fifty yards firing three shot groups for accuracy were fired using the excellent Black Hills Ammunition 52 grain MATCH and the famous and much respected 77 grain SMK. 50 yards isn’t a challenge for these loads and the SIG M400 with three shots falling into .7 to 1.0 inch. Trudging to the 100 yard line I posted a target. At this range the SIG M400 Romeo Red and Black Hill Ammunition 77 grain open tip combination but three bullet holes in 1.5 inch. The Black Hills 52 grain MATCH went 2.0 inches and the 55 grain FMJ 1.6 inch. This is a fine shooter for the price and a rifle that has proven reliable and fast handling.

SIG TREAD M400 SpecsCaliber: 5.56 NATO

  • Weight: 6 lbs. 9 oz
  • Overall length: 32.5 in. (stock collapsed); 35.75 in. (stock fully extended)
  • Receiver: Forged aluminum
  • Barrel: 16″ stainless steel, mid length gas system, 1/8″ twist
  • Muzzle Device: SIG 3-­prong flash hider
  • Stock: Magpul SL-­K
  • Pistol Grip: SIG
  • Forend: SIG 15-­inch M-­LOK
  • Trigger: 7.0 pounds specified, lighter as tested
  • Sights: None delivered
  • Accessories: One 30-­round magazine