The MT6400 went into production in late 2002, with total production just over 5,000 so far.  Am only aware of four variations in the series, that being a change in lower forgings, manufacturers roll mark, upper & carry handle forge codes, and have heard there was two methods to attach the muzzle brake, never noticed myself.

MTM 40XXXX all:

black finish, uppper forge code CAF or Diemaco, carry handle forge code?, M4 buttstock/receiver extention/nut/buffer with the stock pinned to the extention, front push pin, large trigger pins, SPORTER bolt carrier, black extractor buffer & gold spring, roll marked COLT DEFENSE or COLT'S MFG CO. INC, no pinned sear block, pinned on brake, new style side swivel, both the older A2 forging and the modern forging used, M4 handguards

2002

MTM 400XXX A2 lower forging, roll marked COLT'S MFG CO. INC

MTM 400941 Diemaco upper forge code, late lower forging, carry handle forging?, roll marked COLT'S MFG CO. INC

MTM 401314 Diemaco upper forge code, late lower forging, keyhole-4 carry handle forging, roll marked COLT DEFENSE

2003-2004 (just a guess)

MTM 401755 CAF upper forge code, late lower forging, carry handle forging?, roll marked COLT DEFENSE

MTM 402434 Diemaco upper forge code, late lower forging, splinter A and a 2 carry handle forging, roll marked COLT DEFENSE

MTM 402582 late lower forging, roll marked COLT DEFENSE

MTM 402XXX late lower forging, roll marked COLT'S MFG CO. INC, lower only

MTM 403124 Diemaco upper forge code, late lower forging, bird's head carry handle forging (need to look, but am pretty sure), roll marked COLT DEFENSE

MTM 403244 late lower forging, roll marked COLT'S MFG CO. INC, has a custom chrome job

MTM 403700 Diemaco upper forge code, late lower forging, bird's head carry handle forging, roll marked COLT'S MFG CO. INC

MTM 4040XX C Keyhole upper forge code, Cardinal carry handle forging , marked COLT'S MFG CO. INC, purchased in June of 2004, birth bag was marked March 2004.

MTM 404151 upper forge code?, late lower forging, carry handle forging?, roll marked COLT'S MFG CO. INC

MTM 4041XX upper forge code?, late lower forging, carry handle forging?, roll marked COLT'S MFG CO. INC, this one has a C keyhole upper, but is a custom rifle

MTM 404351 upper forge code?, late lower forging, carry handle forging?, roll marked COLT'S MFG CO. INC


2005 (another guess)

MTM 4050XX C keyhole upper forge code, late lower forging, carry handle forging?, roll marked COLT'S MFG CO. INC

Post yours and I will add it to the data base

tag

There was only a few thousand, but I know some of you guys have one.

Quoted: There was only a few thousand, but I know some of you guys have one.

Here's mine:

Box Marked:
MT6400C
Lower Marked:
Match Target M4 Carbine, Serial Number 401XXX, Colt Defense
Upper Marked:
C AF
Carry Handle Marked:
Keyhole-4

I suppose the roll-mark change from Colts Mfg to Colts Defense is consistent with the company split in 2002

Only 5,000? Surprising- and that many subtle variations in just 3 years production is an idea of how fluid the base parts industry is.

Quoted: I suppose the roll-mark change from Colts Mfg to Colts Defense is consistent with the company split in 2002 Only 5,000? Surprising- and that many subtle variations in just 3 years production is an idea of how fluid the base parts industry is.

I don't think there were that many, highest serial found so far is 4,2XX.

MT6400C manufacturer's roll mark appears to be random.

Quoted: I don't think there were that many, highest serial found so far is 4,2XX. MT6400C manufacturer's roll mark appears to be random.

 I have one that is MTM #4050XX, so they did go over 5,000 (I assume).  Lower says Match Target M4 Carbine, Cal .223.  Can't find anything on the upper except a keyhole and a C.

 

Quoted: Quoted: I don't think there were that many, highest serial found so far is 4,2XX. MT6400C manufacturer's roll mark appears to be random.  I have one that is MTM #4050XX, so they did go over 5,000 (I assume).  Lower says Match Target M4 Carbine, Cal .223.  Can't find anything on the upper except a keyhole and a C.

Apparently so, good stuff.  That must be one of the last ones?  Is is COLT DEFENSE, or COLT MFG INC?  Considering it is the highest serial number we know of, the barrel date would be nice.  It is located directly behing the handguard cap on the barrel under the guards.

Bought my MT6400C in June of 2004,the bag the rifle was wraped in was marked March 2004.

Lower marked : Match Target M4 Carbine  Serial Number,MTM 4040XX  COLT MFG CO.INC

Upper marked : C Keyhole

Carry Handle marked : Cardinal

Quoted: Apparently so, good stuff.  That must be one of the last ones?  Is is COLT DEFENSE, or COLT MFG INC?  Considering it is the highest serial number we know of, the barrel date would be nice.  It is located directly behing the handguard cap on the barrel under the guards.

 It says COLT MFG, INC.  I will have to get back to you regarding the barrel date.

Updated.

is there a database for 6920's and the such?

Sure:

www.ar15.com/forums/topic.html?b=3&f=118&t=270885

There are a bunch of them, do a search on posts by Ekie in the AR15 section to find the rest.

Here goes,



Mike Mers

tagged