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Posted: 6/3/2008 5:32:32 AM EDT
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I was wondering about the date that chrome barrel lining was started. I read the components guide and found a date for chrome chamber : "Starting in October 1967 and prior to serial number 800,000 Colt’s added chrome to the chamber. Chrome chamber barrels are identified by a C about an inch back from the muzzle rather then the earlier 12" I could not identify when a chrome bore without a chrome chamber was started. Can anyone point me to the info on when chrome bores were started ? |
From Retro Black Rifle:
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Once the barrels had a chrome "bore" that included the chamber as well....there were no chromed barrels WITHOUT a chromed chamber. |
Hmmm... I didn't think that, but found this:
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Yes, chrome chambers first, and then chrome chambers + bores. I got an exact date on when the chrome was added to the bores, think it was December of 1971. Those would be the C MP B barrels, and the serial numbers were around 4.7 mil at the time. Eugene Stoner did not feel that a chrome bore was needed, in that ArmaLite had switched to the U.S. Army Ordnance endorsed CMV (from stainless steel/aluminum composite barrels) just prior to the development of the AR-15. He consider chrome to be "gold plating" considering the quality of the CMV barrel steel. In addition testing at Aberdeen, Fort Benning, Fort Ord, Fort Greely, etc during the 1958-59 time frame did not show any need for chrome plating the chamber or bore. In fact the AR-15 out performed the T-44E4 control rifles at Fort Benning in reliability (interesting side note, the T-44E4 also lacked a chrome chamber/bore). Contrary to TBR chrome plating of .224 bores was feasible in the 1950's, William Davis at Aberdeen was playing with a chrome bore "5.56x51" rifle back in 1955. Marker Machine Company, Charleston, IL had plated the bore for them |
Not sure, but the AK47 was chromed from the begining. The U.S. Ordnance requirement for chrome bore small arms dates to the mid-1950's. The initial development of the AR-15 fell outside of the authority of U.S. Ordnance, it was spurred by CONARC. BTW, AR-15/AK47 barrels are not chrome lined, they are chrome plated. |
Not sure why, but I had decided they started with chrome plating the bore and then the chamber later. So, I had found the chamber date and then been trying to work backwards Just a reminder not to assume anything ... |
I don't know where it started, but certainly the Russians were huge fans of the concept, and I think every PPS 43, which is possibly the cheapest SMG ever issued, was still made with a chrome bore and chamber. By mid war, I believe every small arm in production in Russia was coming out with a chrome bore.
Aren't the two terms synonymous? I don't think anyone exclusively associates the term "chrome lined" with a fabricated liner that is swaged into place, do they? |
While the term "chrome lined" bores is in common usage, it is still inaccurate slang. |
| Now it has been a while, but I read in a couple of sources, that the chambers specifically had been left unchromed, probably as a cost saving measure. And then due to problems with the rifles in SE Asia, the Army ordered that subsequent rifles have chromed chambers "to aid extraction". Two of the books I read that contained this information were "The M-16" by Jean Huon and "Guns in Combat". Unfortuneatly, I don't know the name of the author to the second one. I suppose it could be a typo, but I remember it specifically mentioned the chamber in those. Unless, I'm losing my mind. |
 They used to advertise in the "American Rifleman" Had them do an M1 carbine for me back around 1954. So as not to make the bores too small, they only plated to a thickness of about half a thousanth; and after 2-3000 rounds the plating started to peel from the chamber forward. 
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I tossed that out as a bit of trivia, had no idea anyone would know who they are, I never heard of them before. |
The info I provided on Stoner's reasoning on no chrome came from testomony to congress:
Colt was the one that proposed chroming the chamber, they did so on 17 April 1967, and was approved by Rock Island on 26 May 1967, and then it was delayed by the UAW strike at Colt. Like Poyer's book, best not to read the text in Huon's M16 book (other then for humor), I have one just for the pictures. |
I just picked up some 1950 issues of "American Rifleman." Marker Machine Co. was advertising their bore plating services back then as well. A Weatherby ad also played up the advantages of the optional chrome-plated bores in their custom barrels and rifles. |
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