!rare ar15 barrel identification help! Please

i recently purchased a barrel i have never seen before, ive spent hours searching pictures with not even a remote similarity, this bbl is C colt marked on the FSB on the underside of the barrel(18"bbl), its made of stainless steel..and has the original SP1 light profile, i just got my AR back today and have not shot it yet, but im trying to get some more info..my friend who has connections to buy these "rare" parts insures me its a colt..i paid 175$ new..but no idea on twist rate, year of manufacture..i do not have any pictures yet...the only marking on this barrel is that TINY colt C thats it! IM SO FRUSTRATED:banghead: and happy at the same time to own such a rare barrel, its not everyday you find a Colt SP1 stainless steel barrel--SO PLEASE HELP ME GET INFO ANY IS APPRECIATED!!! i really need to know the twist rate and what the differance between a regular sp1 bbl and SS are? and production year

thanks i will try that! have you ever heard of a SS SP1 barrel?

thats close but mines 18"s...and is polished SS...does anyone know the twist

sorry guys this barrel actually measures 19"s(not quite 20?) which is weird! and it has not been chopped or modified, it came sealed in bubble wrap with rubber thread protector on the muzzle threads(no A2 sight holes drilled though).so it is definitely a new factory barrel, I haven't tried Colt yet because im thinking all i have to go on is the tiny 2.5MM "C" marking by the gas block, no other markings what so ever, the guy who sold and installed the barrel is a Professional Custom AR15 builder and really knows his parts, hes a die hard Colt freak, so i do believe him. i talked to him today about it, and he said "its a colt, no other company uses that specific "C" it is very distinguishable" he bought 4 of these barrels from an unspecified source..only said that they were from a close friend who had them for a long time in a gun vault.and are extremely rare. the profile of it is unique, looks just like a Vietnam era barrel only shiny SS..Also you can see the lathe marks on the barrel im completely stumped again its SP1 style light profile in stainless steel only marked with a single tiny C
PICTURES WILL BE UP SOON, THANK YOU FOR THE HELP, PLEASE KEEP POSTING I REALLY WANT TO FIND SOMEONE WHO HAS SEEN OR HEARD OF THIS BARREL BEFORE

@ shear-stress......yes my barrel is that exact profile!, but is real SS

rcmodel said:

How did you determine it is stainless steel and not just a normal steel barrel that missed going through the Parkerizing tank?
Will cold blue do anything on it for instance?

Any evidence it is chrome lined?
Flatter whiter color at the muzzle and chamber ends?

rc

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I just compared the barrel to two other Stainless barrels, a 17HMR, and a RRA heavy SS barrel, the cold blue made a tan-rust color so i guess its possible it missed parkerizing? but the barrel looks VERY similar to my other comparisons, the only REAL difference is the lathe tool marks from MFG...other than that no sign of chrome lining(compared it to a AK47 bbl) So have there been reports of Colt bbls that missed parkerizing-that go to the retail market? but if it is a odd ball barrel its pretty cool! thanks for that info..im uploading pics now

(The "C" by the gas block)






(the complete rifle)





PLEASE COMMENT IM OPEN TO ANY AND ALL OPINIONS!!!

this is the best pic i have right now, and i just put a new crush washer on so i cannot remove the flash suppressor unfortunately...i will have BETTER pics very soon...THANKS AGAIN GUYS!!!!much appreciated

Please any one with any info please!!!!post

hardluk1 said:

The picture showing the handguard and barrel up to the flash hiderlook as if there is rust or tarnishing on the barrel. The pictures are just not clear enought to help. If the barrel is in the white as in a carbon steel ,does it have a chrome bore. Early barrels had NO marks and no chrome bores . Maybe an unfinished steel barrel that never made it to finish work while barrels in general were updated to chrome bores. I see at auction site sp1 finshed barrel sell for 175 to 200 . Contact colt and see if anyone can help.

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yea in the picture it does look tarnished, but it isnt its just as shiny as my Savage 93R17FVSS barrel, my camera sucks really bad so the quality is awful, it does not appear to be chrome plated at all and is lacking the signature white band on chrome lined bbls, in all honesty it Appears to be authenic SS...i did a "Patch Twist test" and it seems to be a 1:9 twist bbl....so i guess the 2 questions are now this, HAS ANYONE SEEN A BARREL LIKE THIS?? SS or unfinished carbon steel??? and is there a WAY TO CHECK IF ITS ACTUALLY SS? thanks for helping guys...please keep the input rolling!!!