[G-nineteen]

Is it a generic gun with widely-available parts or does it have proprietary parts that are hard to get?

 

[Travclem]

Standard AR parts.

 

[G-nineteen]

Standard AR parts.

Thanks.

I may want the location of that "house" in your signature.

 

[Ruggles]

A friend of mine bought one last last week, seem like a great rifle.

 

[WoodenPlank]

I'm still skeptical of SIG's AR offerings. As other folks have rightly pointed out in the past, they have had QC issues with pistols and rifles of their own design lately. That doesn't bode well for them building someone ELSE'S design.

Good news is they should be all standard(ish) parts, so replacing anything that turns out to be crap shouldn't be hard.

 

[LA_357SIG]

The barrel extension is not standard, but will accept a standard bolt.

 

[boomhower]

I believe it does have some non standard parts but it will take any standard replacement part or accessory. I'd stay far far away from the 556 but the M400 should be just fine and I'd wouldn't mind getting my hands on a 516.

 

[WoodenPlank]

The barrel extension is not standard, but will accept a standard bolt.

First I have heard of that. What's the difference?

 

[MrMurphy]

They can't manage to build their OWN designs they've been building for 30 years right.

They have zero experience building ARs.

I'll stick with the known quantities.

 

[vettely]

The barrel extension is not standard, but will accept a standard bolt.

Hidden inside, just aft of the chamber, is a protrusion that lines up with the extractor when the bolt is in battery. This button-like addition supports the extractor body when the gun is fired. Only 1⁄3 of an AR’s extractor is contained within the barrel extension when the bolt is fully in battery, leaving the remaining length retained only by the extractor pin that also acts as a hinge for normal function. The extractor is a common first point of failure when a cartridge case head ruptures due to excessive pressure or lack of sufficient support. Since it is the weak point in the bolt’s encirclement of the case rim, the extractor takes the brunt of excess gas pressure and is typically pushed outward far enough to break or bend both the extractor and the extractor pin. This can result in a ruined bolt-carrier assembly and possibly even destroy the upper receiver. While the level of pressure necessary for this type of failure often ruins other parts of the firearm, supporting the extractor adds an extra element of support to help contain pressure at the case head by preventing the rear of the extractor body from being pushed away from the bolt and into the upper-receiver wall.

 

[Ruggles]

Hidden inside, just aft of the chamber, is a protrusion that lines up with the extractor when the bolt is in battery. This button-like addition supports the extractor body when the gun is fired. Only 1⁄3 of an AR’s extractor is contained within the barrel extension when the bolt is fully in battery, leaving the remaining length retained only by the extractor pin that also acts as a hinge for normal function. The extractor is a common first point of failure when a cartridge case head ruptures due to excessive pressure or lack of sufficient support. Since it is the weak point in the bolt’s encirclement of the case rim, the extractor takes the brunt of excess gas pressure and is typically pushed outward far enough to break or bend both the extractor and the extractor pin. This can result in a ruined bolt-carrier assembly and possibly even destroy the upper receiver. While the level of pressure necessary for this type of failure often ruins other parts of the firearm, supporting the extractor adds an extra element of support to help contain pressure at the case head by preventing the rear of the extractor body from being pushed away from the bolt and into the upper-receiver wall.

Good info, thanks :wavey:

 

[vettely]

Good info, thanks :wavey:

Cut from this article. M400 also has several other nice features.

http://www.shootingillustrated.com/mobile/article.php?id=20746

 

[Ruggles]

Cut from this article. M400 also has several other nice features.

http://www.shootingillustrated.com/mobile/article.php?id=20746

I will share with my friend who just bought one. :wavey:

 

[G-nineteen]

I avoid the first-model-year of new cars. I know Sig has only a short, unflattering history with ARs.

The M400 has been out only a year or so? Surely a number of people have put thousands of rounds through theirs.

Wouldn't any (Sig)-nificant flaws have been discovered by now?

I had the Sig Mosquito for a few months before selling it because it was a jam master.

The M400 is probably not a great AR. Is it not a solid value deserving of a chance to be tested before being put into Home Defense duty?

 

[WoodenPlank]

I avoid the first-model-year of new cars. I know Sig has only a short, unflattering history with ARs.

The M400 has been out only a year or so? Surely a number of people have put thousands of rounds through theirs.

Wouldn't any (Sig)-nificant flaws have been discovered by now?

I had the Sig Mosquito for a few months before selling it because it was a jam master.

The M400 is probably not a great AR. Is it not a solid value deserving of a chance to be tested before being put into Home Defense duty?

Not necessarily. Many times flaws in design or workmanship aren't able to be found until the item is nearly driven to the point of destruction. With a firearm in the hands of an average owner, that point can take months or years to reach. Unless there are a large quantity of SIG M400s in the hands of people that shoot several throusand rounds per year, there isn't likely to be a large enough pool of well-used guns out there to really make much of a conclusion from anecdotal evidence.

A few years from now, such a conclusion will be easier. Right now, though, the SIG DI rifles still remain a very unknown quantity.