By now everyone should be pretty well aware of my affinity for fine AR platform rifles.
I have fired many rounds through many different manufacturers. From Armalite to newcomers like Daniel Defense.
I have tried both piston and direct impingement gas systems.
Innovation in the firearms industry happens very fast. But unfortunately the AR platform has received very few innovative design changes in the last
50 years with exception of cosmetic systems.
Sig Sauer, I believe, has changed that with the M400. How? How is a DI gas based AR platform so innovative that it requires it's own thread on ATS?
The changes are not that big. But they are IMPORTANT. The small changes made to the M400 contruction not only make the weapon extremely reliable, it
also makes it inexpensive while maintaining the high quality construction known of Sig firearms.
Let us begin with the chamber. There is a pin in the chamber that keeps pressure on the extractor. The purpose of this is to mitigate the forces
placed on the extractor and extractor pin by over-pressure events. But it also has the added benefit of reinforcing the extractor to effectively
control failure to extract malfunctions that are common to AR based platforms. This means that firing steel cased ammo, which expands in the chamber
due to heat and pressure, is no longer an issue.
The lower receiver also has a good tweak. It has a magazine release on the left side which allows the firing hand to stay on the trigger during
The "Wobble" or "play" between the upper and lower receivers is completely non-existent in the M400. This is a HUGE point of contention between the
M400 and pretty much EVERY high end tactical rifle manufacturer. This is accomplished by a detent located at the rear takedown pin which creates
upward pressure on the upper receiver and the take down pins are tight and there is no play at all.
It comes standard with a 1:7 twist rate ideal for heavier 5.56mm rounds.
The trigger is lighter than most stock triggers. 5 lbs. Most stock triggers are between 8 and 12 lbs which can be a real problem when accuracy is
paramount. If you're anything like me, a 5lbs trigger is still not good enough..And yes, you guessed it, I replaced mine with a 1.5lbs trigger
assembly from Jard
This is really not your typical AR. For less than 1000 bucks you have a well constructed and accurate weapon by a known and respected manufacturer.
There is more weapon here than I have found in many "high end" AR based weapons.
It is well worth the money.
3000 different rounds of varying quality and manufacture. 1500 steel case and Russian zinc and lacquer coated rounds, for a total of 4500 rounds and
not ONE malfunction to report.
edit on 28-10-2012 by projectvxn because: I added an image of the weapon