1990

ST 0016xx, CM forge code, raised mag fence lower, large (.312) pivot, no weep hole, no sear block, std FCG, SPORTER bolt carrier, marked COLT’S FIREARM DIVISION, barrel stamped C MP 5.56 NATO 1/7

ST 001XXX CM forge code, mag fenced lower, big pivot pin, no sear block, marked COLT’S FIREARMS DIVISION (this one has a FA carrier, bayonet lug, and tear drop forward assist, maybe replacement parts?)

GS 010173 CM forge code, slab side lower, no sear block, small hammer/trigger pins, marked COLT'S MFG CO. INC,

ST 004600 and up have large trigger/hammer pins

ST 005293 CM forge code, mag fenced lower, big pivot pin, no weep hole, sear block pinned on both sides, large hammer/trigger pins, marked COLT'S MFG CO. INC

1991

ST 007XX1 CM forge code, mag fenced lower, big pivot pin, no weep hole, no sear block, large hammer/trigger pins, marked COLT'S MFG CO. INC, barrel marked C MP 5.56 NATO 1/7, puchased new in fall of 1991

ST 008361 mag fenced lower, big pivot pin, no weep hole, sear block pinned in on both sides, marked COLT'S MFG CO. INC, this a M4gery conversion painted black

1992

ST 009999 mag fenced lower, big pivot pin

ST 010254 CM upper forge code, slab side lower, roll marked COLT'S MFG CO. INC, sear block pinned in on right side

1993 - Sept 94

ST 017XX9 mag fenced lower, small pivot pin hole, weep hole drilled, marked COLT'S MFG CO. INC., sear block pinned in on right side, this is lower only

ST 01776X CM upper forge code, mag fenced lower, small pivot pin hole, weep hole drilled, marked COLT'S MFG CO. INC., sear block pinned in on right side, SPORTER bolt carrier

ST 025289 CMB upper forge code, mag fenced lower, small pivot pin hole, weep hole drilled, marked COLT'S MFG CO. INC., sear block pinned in on right side, SPORTER bolt carrier, blue extractor buffer

ST 026376 CMB upper forge code, mag fenced lower, small pivot pin hole, weep hole drilled, marked COLT'S MFG CO. INC., sear block pinned in on right side, SPORTER bolt carrier, blue extractor buffer (purchased the summer of 94)

ST 0287XX CMB upper forge code, mag fenced lower, small pivot pin hole, weep hole drilled, marked COLT'S MFG CO. INC., sear block pinned in on right side, SPORTER bolt carrier, blue extractor buffer (purchased new in September or October 1994)

ST 0289XX CMB upper forge code, mag fenced lower, small pivot pin hole, weep hole drilled, marked COLT'S MFG CO. INC., sear block pinned in on right side

ST 033670 mag fenced lower, small pivot pin hole, weep hole not drilled, marked COLT'S MFG CO. INC., sear block pinned in on both sides

ST 0354XX CMB upper forge code, mag fenced lower, small pivot pin hole, weep hole not drilled, marked COLT'S MFG CO. INC., sear block pinned in on both sides

Sept 94 on (bare muzzle, and SPORTER roll markd changed to MATCH TARGET from this point)

CST 003783 CMB upper forge code, mag fenced lower, small pivot pin hole, weep hole drilled? marked COLT'S MFG CO. INC., sear block pinned in on both sides

CST 0XXXXX black finish, does not appear to have a pinned in sear block

Here's mine:

ST 0287XX CMB upper forge code, mag fenced lower, small pivot pin hole, weep hole drilled, marked COLT'S MFG CO. INC., sear block pinned in on right side, large trigger/hammer pins, SPORTER bolt carrier, blue extractor buffer.  

This was purchased new in September or October 1994.

Quoted: Here's mine: ST 0287XX CMB upper forge code, mag fenced lower, small pivot pin hole, weep hole drilled, marked COLT'S MFG CO. INC., sear block pinned in on right side, large trigger/hammer pins, SPORTER bolt carrier, blue extractor buffer.   This was purchased new in September or October 1994.

Got it in there, thanks.

OK...a bit newb on all the Colt variations...and there are a lot.  What would serial # ST 00122X be?  Marked Sporter Target Model.  Even earlier than the serials you listed?  Thanks,

dvo

Quoted: OK...a bit newb on all the Colt variations...and there are a lot.  What would serial # ST 00122X be?  Marked Sporter Target Model.  Even earlier than the serials you listed?  Thanks, dvo

Same thing, just an older 6551.

What do you make of the change from "ST" to "CST"?

Company structure change?

(just realized it may be the Match target designation, from Sporter)

Quoted: What do you make of the change from "ST" to "CST"? Company structure change? (just realized it may be the Match target designation, from Sporter)

Yep, dropped the SPORTER name and went to MATCH TARGET, serial number prefix changed too.

ST 007XX1 Mag fence, no sear block, lg pivot pin, lg FCG pins, CM forge code, C MP 5.56 NATO 1/7,  Purchased new Fall of 1991.

My R6551:

ST 0016xx, CM forge code, raised mag fence lower, large (.312) pivot, no weep hole, no sear block, std FCG, marked COLT’S FIREARM DIVISION, barrel stamped C MP 5.56 NATO 1/7.  One of the earlier ones I guess.

OK, got those in there.

Also found a TARGET MODEL 6551 with a GS serial number, know it dates from 1990, but not sure where to put it in that year.

Quoted: My R6551: ST 0016xx, CM forge code, raised mag fence lower, large (.312) pivot, no weep hole, no sear block, std FCG, marked COLT’S FIREARM DIVISION, barrel stamped C MP 5.56 NATO 1/7.  One of the earlier ones I guess.

Does this one have a bayonet lug?  Is the carrier full circle?  What kind of forward assist?

Quoted: OK, got those in there. Also found a TARGET MODEL 6551 with a GS serial number, know it dates from 1990, but not sure where to put it in that year. Quoted: My R6551: ST 0016xx, CM forge code, raised mag fence lower, large (.312) pivot, no weep hole, no sear block, std FCG, marked COLT’S FIREARM DIVISION, barrel stamped C MP 5.56 NATO 1/7.  One of the earlier ones I guess. Does this one have a bayonet lug?  Is the carrier full circle?  What kind of forward assist?

No bayonet lug, not a full circle carrier, std round forward assist.

Quoted: Quoted: OK, got those in there. Also found a TARGET MODEL 6551 with a GS serial number, know it dates from 1990, but not sure where to put it in that year. Quoted: My R6551: ST 0016xx, CM forge code, raised mag fence lower, large (.312) pivot, no weep hole, no sear block, std FCG, marked COLT’S FIREARM DIVISION, barrel stamped C MP 5.56 NATO 1/7.  One of the earlier ones I guess. Does this one have a bayonet lug?  Is the carrier full circle?  What kind of forward assist? No bayonet lug, not a full circle carrier, std round forward assist.

Thanks, that ST 001XXX is a couple hundred from yours, and has some odd features, so good to know.

No problem Ekie, this informational database is cool.  Just for the record, I am not the original owner of this R6551 so I don't know what color label box it came in (I'm assuming blue but there was a short time when white labels were used), but the person I bought it from told me the rifle was 100% original, parts-wise, as it came in the box.  As you say, maybe the other ST 001xxx rifle has some replacement parts.

The only thing that's certain with regards to the early 90's transition from Colt's Firearms Division to Colt's Manufacturing Co, Inc. is that nothing is certain, hehe.

Quoted: No problem Ekie, this informational database is cool.  Just for the record, I am not the original owner of this R6551 so I don't know what color label box it came in (I'm assuming blue but there was a short time when white labels were used), but the person I bought it from told me the rifle was 100% original, parts-wise, as it came in the box.  As you say, maybe the other ST 001xxx rifle has some replacement parts. The only thing that's certain with regards to the early 90's transition from Colt's Firearms Division to Colt's Manufacturing Co, Inc. is that nothing is certain, hehe.

Both of those 1,000 series ST's are a bit odd, then toss in the GS prefix rifle too for good measure.  Think there is a GS prefix carbine in the 6520 base too?  Sure, hard to be certain with anything Colt.  More data we get, the more certain we can be though.