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3/26/2009 7:59:24 PM EDT
Got a buddy who contacted me about an SP1 barrelled upper that he picked up, and the front sight base is forged and machined smooth. He's wondering if this would be correct for an SP1 build?
3/26/2009 9:36:19 PM EDT
[#1]
Depending on the year, it very well could be.   The earlier SP1s had the smooth FSBs.  The very first ones were cast.
3/26/2009 10:08:42 PM EDT
[#2]
Not trying to be a smart-ass here, but if it's an SP-1 upper, then it's an SP-1 upper!



What about this, specifically, has you concerned?

Is it, in fact, an SP-1 upper receiver?

Barrel marked 12 or C MP B or C MP C?

Three-prong flash hider?



If you suspect the barrel isn't original to the receiver, then it's still okay (assuming it has the Colt markings per the above) because the early style you describe was the only thing available until about 1967-69.

You can get an idea of when the variously-marked barrels were produced here.



It's just a matter of what you want to build.  If you have an SP-1 lower, check the serial number and that will tell you what year it was made.

If it came after about 1968, you would technically want the later style. Or not.



If your SP-1 receiver has a later serial number, you could sell the early barrel for more than it would take to buy the later Colt barrel.

Check serial numbers here. Or here. Or here.



Google is your friend. Use it.




Quoted:


Got a buddy who contacted me about an SP1 barrelled upper that he picked up, and the front sight base is forged and machined smooth. He's wondering if this would be correct for an SP1 build?






 
3/27/2009 5:25:01 AM EDT
[#3]
Quoted:
Not trying to be a smart-ass here, but if it's an SP-1 upper, then it's an SP-1 upper!

What about this, specifically, has you concerned?
Is it, in fact, an SP-1 upper receiver? Yes, large pivot pin hole
Barrel marked 12 or C MP B or C MP C? C MP C
Three-prong flash hider? He didn't specify whether it had one or not

If you suspect the barrel isn't original to the receiver, then it's still okay (assuming it has the Colt markings per the above) because the early style you describe was the only thing available until about 1967-69.
You can get an idea of when the variously-marked barrels were produced here. Retro Black Rifle doesn't cover civvy models yet

It's just a matter of what you want to build.  If you have an SP-1 lower, check the serial number and that will tell you what year it was made.
If it came after about 1968, you would technically want the later style. Or not. I did ask about the lower. He just bought the barreled upper

If your SP-1 receiver has a later serial number, you could sell the early barrel for more than it would take to buy the later Colt barrel.
Check serial numbers here. Or here. Or here. Again, no lower is present

Google is your friend. Use it.


 



Thanx for the input.
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