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Posted: 12/22/2019 9:37:25 PM EDT
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All,
I'm looking for input on developing a timeline for bolt carriers and bolts. For bolt carriers I have the following information: Chrome bolt carrier with full round gas key tube (1959 - 1963) Chrome bolt carrier with partial round gas key tube (1963 - 1965) Slickside parkerized bolt with carrier with chrome gas key (1964 - 1966) Slickside parkerized bolt carrier (1966 - 1970) Chrome bolt carrier with forward assist serrations and full round or partial round gas key tube (1964 - 1967) Parkerized bolt carrier with large countersink at retaining pin (1967) Parkerized bolt carrier with small hole at retaining pin (1967 - 1968) Parkerized bolt carrier with C stamp (1968 - 1982) Parkerized GM bolt carrier (1968 - 1971) Parkerized H&R bolt carrier (1968 - 1970) For bolts I have the following information: Chrome bolt with thin band with no oil drain hole; extractor lug tapered at front and square at back (1959) Chrome bolt with thin band and P marked at the lugs; extractor lug tapered at front and square at back (1960) Chrome bolt with thin band and M P marked at the lugs; extractor lug tapered at front and square at back (1960 - 1963) Chrome bolt with thin band and M P marked at the lugs; extractor lug tapered at front and back (1963) Chrome bolt with wide band and M P marked at the lugs; extractor lug tapered at front and back (1963 - 1964) Parkerized bolt with wide band an M P marked at the lugs; extractor lug tapered at front and back (1964 - present) For firing pins I have the following information: Fat Head firing pin (1959 - 1963) Flat Head firing pin (1963 - 1965) Modern firing pin (1965 - present) For firing pin retaining pins I have the following: Machined firing pin retaining pin (1959 - 1965) Cotter pin for firing pin retaining pin (1965 - present) I invite all recommended changes. Thanks. Standing by... |
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Bob;
From my notes, I show the following differences: Chrome bolt carrier with full round gas key tube (1959 - 1963) Chrome bolt carrier with partial round gas key tube (1963 - 1965) Slickside parkerized bolt with carrier with OR WITHOUT chrome gas key (1964 - 1966) Chrome bolt carrier with forward assist serrations and full round or partial round gas key tube (1964 - Parkerized bolt carrier with large countersink at retaining pin (1966-1967) Parkerized bolt carrier with small hole at retaining pin (1967 - 1968) Parkerized bolt carrier with C stamp (1968 - 1982) TWO VARIATIONS Parkerized GM bolt carrier (1968 - 1971) Parkerized H&R bolt carrier (1968 - 1970) For bolts I have the following information: Chrome bolt with thin band with no oil drain hole; extractor lug tapered at front and square at back (1959) Chrome bolt with thin band and P marked at the lugs; extractor lug tapered at front and square at back (1960) CHROME BOLT WITH THIN BAND AND P MARKED AT THE LUGS; EXTRACTOR LUGS TAPERED AT FRON AND BACK (1961-1962) Chrome bolt with thin band and M P marked at the lugs; extractor lug tapered at front and back (1962-1963) Chrome bolt with wide band and M P marked at the lugs; extractor lug tapered at front and back (1964 - 1966) Parkerized bolt with wide band an M P marked at the lugs; extractor lug tapered at front and back (1966 - Fat Head firing pin (1959 - 1963) Flat Head firing pin (1963 - Modern firing pin (1967 - present) For firing pin retaining pins I have the following: Machined firing pin retaining pin (1959 - Cotter pin for firing pin retaining pin (1966 - present) |
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Tom,
Thanks a bunch for your recommended changes! With regard to the 604 bolt carrier, it was my understanding that the early parkerized bolt carriers all had the chrome gas key until the gas key finish was changed from the chrome finish to parco-lubrite (parkerized) in September of 1965 (as indicated in the Report of the Rifle Review Panel). With this, I thought that the parkerized bolt carriers with the chrome gas key were considered the "transitional" bolt carriers and the later all-parkerized versions were the standard 604 bolt carriers. I also understand that the production of slick-side bolt carriers were stopped at some time in favor of using only the standard forward assist notched bolt carrier. Do you know when this change was made? Also, you noted that there were two versions of the C-stamped bolt carriers. Do you have any more information as to what the two types were and in what time periods they were used. Thanks again! Bob |
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Tom,
Also, with regard to the machined firing pin retaining pins, the Report of the Rifle Review Panel indicates that the firing pin retaining pin was revised in accordance with engineer drawing GX-5977 in September 1965. Do you have information showing the date as being 1966 as you have referenced? Thanks for bouncing these ideas around! |
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Quoted:
Don't forget the diagonal serrations on early bolts just behind the locking lugs. Not sure what dates, but early. My very early 604 has Chrome BCG, fat head FP, serrated bolt, early extractor and Parkerized key. |
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