Colt ar15 sp1 1977

[Dr.Rob]

That's a great looking rifle. I set up my 6920 for that XM look a while back with a slip-over flashhider. Did it sell?

[halfmoonclip]

For the OP, as was noted earlier, make damned sure that the flash hider is either pinned or welded; putting a setscrew in that hole and then getting a spot of weld on top should be enough to solve the problem.
I'm inclined to agree with the Judge and assume the barrel has been replaced. Is it chrome lined? Again, it's my impression that Colt barrels were marked with caliber and 'chrome lined', if they indeed were. The upper has the right markings for Colt production.
Moon

[halfmoonclip]

Double tap.
M

[CAR]

You might want to check and see if the flash hider is one of the slipover kind. I had one on my rifle back in the 80's, they were a way to make a 16' barrel look like a short barrel and were quite popular in the 1980's. The lack of a forward assist and the aluminum stock are correct for your rifle, the upper receiver is marked CM which is correct as well.

EDIT: After looking closely at the pics, it does appear that the barrel is short and does not have one of the slipover flash hiders.

[chuter]

Greatbarracuda: the carbine is made to look like the XM-177/CAR-15 w/o the forward assist and with the legal 16" barrel length. For the civilian market, the flash suppressor is welded to the barrel. Mine is of similar vintage. When I converted it to Class III (back in the day when you still could do that) I added the "squad" barrel, like you have on your carbine. The barrel should be slightly heavier/thicker than the stock SP barrel and will accept the .223 or 5.56 round with ease. It was slightly heavier in anticipation of more full auto firing. It's a great looking gun. Is that a Colt 3x scope too? In our neck of the woods, at local gun shows that's a $1,600 carbine (and that's at the low end).

[AMAC]

Nice weapon