I've had this rifle for years, I got it from my friend who had to move away to California.
This is a KAC (marked KMC, Knight's Manufacturing Company) Stoner Rifle SR-15 M4.
The roll marks on this rifle are not engraved, they look almost like inlays or maybe just painted on.
If I take off the top rail it's dated 6/10/2001.
This rifle came with a A2 stock and rifle buffer but the barrel is 16" carbine length. I was wondering why it was built this way.
Mostly every other one I've seen came with what looks like a pinned 14.5 barrel but mine is a 16" carbine.
I've also heard these are non-chrome-lined match barrels and they are also equipped with a 2-stage match trigger.
What can you tell me about these rifles?

Knights M4 barrel
-The muzzle device is a pressed on faux-FH on a 16” barrel
- Barrel is NOT threaded
-1:7 twist
-Non chrome lined match
-Krieger manufactured

Post ban gun. Since it had a pistol grip and detachable mag it couldn’t have any other features like a collapsible stock, bayonet lug and etc. Its also pre E3

That's a cool rifle.

How does that work, muzzle device slipped over barrel and pinned?

It doesn't have to be pinned since the barrel is originally over 16" and the faux-FH only had superficial cuts made to look like a flash hider but had no effect like a birdcage would.

That doesn’t appear to be the case for the rifle/barrel pictured.

You can clearly see through the slots on the muzzle device and it appears to have been threaded on.

Just pressed on.....getting them off is a biOtch

I really didn’t look at the one above much. Was just speaking of direct experience of owning a Knights M4.

That one has been dorked with after it left KAC, muzzle device looks to be a Yankee Hill Machine.

Muzzle device is a YHM phantom flash hider and it is threaded on. Not sure if my friend removed the pressed on flash hider and had the barrel threaded but I could ask him. It does appear to be the original barrel though, I can tell it is not chrome-lined.

That's what I was thinking too.

None of the SR-15 M4 barrels I've ever owned had chamber or twist markings either.

Yea, neither was this barrel. My friend told me it's 1/7 twist but I've heard they are 1/9.

They are a 1:7, non chrome, Kreiger barrel.