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View Full Version : Requesting information on Colt barrels.


PrarieDog
11-22-10, 21:39
I was checking out a friend's older Colt the other day and was suprised by the fact that it had a 1/7 barrel stamp on it. This is an older slick sided Colt. I was wondering when Colt switched to a 1/7 barrel? I would have figured it would of had a 1/12 or a 1/9 barrel and was suprised that the rate of twist was that fast for an older rifle.
cqbdriver
11-23-10, 05:38
The 1st Colt that I bought in 1986 had a 1/7 barrel. It was an AR-15A2 Sporter II carbine. I believe that they had only been out around 1-2 years.

ETA: Looks like 1984 was the first year according to this:
http://www.biggerhammer.net/ar15/variants/
SouthPark
11-23-10, 12:42
The several pre ban Colts I had all were 1/7, this was in the early 90s.
RAM Engineer
11-23-10, 14:58
ScottRyan can correct me on this, but I think Colt cut the 1/7 barrels into their civilian guns BEFORE they cut the A2 receiver into the line.
scottryan
11-23-10, 15:26
Correct.

The A2 style lower for the civilian guns came out around 1990.

1/7 twist came out in the early/mid 1980s with the M16A2, 727, 723, 733, etc
cqbdriver
11-23-10, 16:13
My Colt from '86 had an SP1/A1 lower with an A1 upper (A1 sight & forward assist, but large pivot pin/screw) and a light wgt 1/7 16" barrel. The Colt 20" rifles were similar at the time (A1 upper & lower, but A2 barrels & furniture).

Around 1990, I got a AR-15A2 Government Model which looked the same as a M16A2 except the large pivot pin(screw). This right after Colt decided that they would sell to civilians again.

When Colt stop selling to civilian around 1989, it caused me to do my first build. What a cluster f#&^! Made every mistake in the book. However, I learned a lot & now I make bigger mistakes.
scottryan
11-23-10, 16:43
A1 sights are not a period specific feature.

They still can be ordered if a customer wants it.

The last run of A1 sighted guns (6320s) was made in 2002 or 2003 I think.
alpha.kilo
11-23-10, 18:27
Colt barrel info seems to be a closely guarded secret. Not to hijack the OP thread, but does anybody know what the gas port is in a Colt 6920 barrel? I believe it to be smaller than milspec, due to the ejection patterning, but have no idea. Also, the 6920 doesn't seem to like extra power buffer springs.

Also, does anybody know for sure that Colt barrels are button rifled? I know Colt Canada produces CHF barrels, but have yet to have a definitive answer on Hartford........