What is the correct finish for a M40 bolt body and handle?
Blued, Turned and polished, Parkerized or something else?
Blued, Turned and polished, Parkerized or something else?
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M40 Bolt Finish
- Thread starter fe1
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60s era rem 700s had polished blued shrouds, bolt handle and bolt nose. Center portion of bolt bodies were usually in the white, polished or jeweled. This wouldn't fly for a sniper rifle, thus matte bluing the entire bolt assembly for the m40
I’ve been told the M40 bolt bodies were like a satin blue but I haven’t found a good detailed pic for comparison.
I do know the commerative M40’s bolt were parkerized but not to sure on the 60’s era M40’s.
Source: Collecting the American Sniper Rifle: 1945 to 2000, by Joe Poyer, page 66. There are various errors in this book, but that info is correct.
Remington didn't bother polishing the M40 bolts to a high-level, and simply hot blued them, resulting in the 'black oxide' finish.
It's the same chemical process b/t "bluing" and "black oxide" - per Wikipedia its an "electrochemical conversion coating resulting from an oxidizing chemical reaction with iron on the surface selectively forming magnetite (Fe2O4), the black oxide of iron."
A highly polished surface with say 1200 grit sandpaper is a very reflective and glossy when the iron is added to the surface - typically called a "blued finish" or "polished blued finish" The same surface but only coarsely sanded with say 80 or 100 grit results in a tiny bit/slightly thicker layer of iron chemically applied in same bluing process, but it results in a very matte, non-reflective surface that some gunsmith's call "black oxide." (I don't know enough about how temperature variation of the bluing solution might impact the surface thickness of the iron, etc).
Surface prep and perhaps length of time a part is immersed in the bluing tank appears to be the main difference, as the chemical process is the exact same - you're chemically adding a very thin layer of iron to the surface, which in its natural form is black (aka black oxide). The downside to black oxide is that it's not especially effective at corrosion resistance compared to other surface treatments, but the upside is that's so thin that it doesn't cause any tolerance 'stacking' issues between precision parts. My 2cts.
(PS: With respect to Parkerizing firearms, or more technically correct "phosphating," one is typically adding a thin layer of manganese (dark grey is its natural color) or a layer of zinc (light/medium gray) to the surface. It doesn't require the surface prep that we associate with 'hot bluing,' hence that is why the military adopted Parkerizing for mass production of firearms early in the 20th century. I understand that it is also not quite as caustic as hot bluing.)
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Random Guy thanks for the article.
The bolt in the pic is not correct for the Vietnam Era due to a couple things I see.
#1 the pic shows a long bolt shroud and the correct shroud is short.
#2 this shows an anti bind groove on the side of the locking lug which was not done until the 70’s.
Although the finish described may be correct for the era.
Not to many articles around on details of the bolt finish so everything needs to be considered.
Thanks Again
The bolt in the pic is not correct for the Vietnam Era due to a couple things I see.
#1 the pic shows a long bolt shroud and the correct shroud is short.
#2 this shows an anti bind groove on the side of the locking lug which was not done until the 70’s.
Although the finish described may be correct for the era.
Not to many articles around on details of the bolt finish so everything needs to be considered.
Thanks Again
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The picture of the bolt may not be correct for a 1966 M40, and might represent a correct 1969 M40 bolt. However, as you noted, the info re finish is correct as Joe Poyner used the Remington Archives for that section of his book, which is what I think you were asking. Black oxide finish is correct (Tip: if you have a commercial bolt that was highly polished or jeweled, it will need to be sanded with coarse sandpaper to mimic an M40 bolt).
This is not an original M40 bolt, but was refinished at PWS with the black oxide finish, same as what Remington used in the late 1960s.
It is from an early 1990's C-prefix rifle, and stamped as done on M40A1s. I recommend trying to mimic this finish on an M40 clone.
Last 4 of serial number engraved on bottom:
Digressing a bit (as I previously noted on your earlier post re M40 and SSA production volumes) there are really two drawings for M40s that Remington used for "Vietnam Era M40s". The first is the 1966 version of the drawing that made up the original M40 order by the USMC, but the drawings were slightly updated in 1968 and again in 1969 with more notable changes, which was also the final revision of the M40 blueprints.
The current/final M40 drawings that Remington maintained (before the recent bankruptcy...) were dated 1969, per the former sales manager for Remington Defense. (Hence the dust-up years ago re shape of the safeties on the SSA and Chuck Mawhinney rifles as Remington used their M40 drawings for those replicas - and the only drawings they maintained at the factory were the last approved ones, dated 1969...but of course customers were assuming the older 1966 configuration with the 'tombstone' shaped safety.)
Joe Poyner's review of the Remington archives shows 15 gov't orders/contracts for a total of 972 M40s delivered to various depts or Arsenals within the US gov't from the years 1966 to 1969. Here's the overview of the archives:.
M40 sniper rifles sold to the US gov't by year:
1966 = 714 (biggest contract was Boston Procurement District for 700 M40s - not specifically noted as to what branch, but this is clearly the original USMC rifle order. Small contract for 6 rifles each for COUSN Regional Financial District and NAVY SPT GRP Pacific)
1967 = 42 (biggest contract was Edgewood Arsenal, MD for 30 M40 rifles, followed by Frankford Arsenal, PA for 7 M40 rifles)
1968 = 81 (biggest contract was Military Air Command, Dover AFB in Delaware for 58 rifles, followed by Frankford Arsenal, PA for 9 rifles, and US Naval Weapons Center, China Lake, CA for 6 M40s)
1969 = 135 (biggest contract was again Boston Procurement District for 105 M40s- unclear from records who received these, but please note that Boston was used for the previous USMC procurement in 66'; and a separate order by US Navy Training Center in San Diego for 30 M40 rifles.)
TOTAL = 972 rifles
(All subsequent USMC orders were just the receiver and probably bolts, but not complete rifles as RTE/PWS was by then building the M40A1/3/5 rifles with the various prefix receivers, C, E, G, etc).
So one could say their were 2 variations of M40s that served USMC Scout Snipers in Vietnam, the initial 1966 variation w/ serialized green scopes + flat face safeties, and short bolt shrouds, etc. And in the later years perhaps a small number of 1969 production that were replacements for rifles lost, damaged or destroyed during the war (ie, for example, Carlos Hathcock's M40 that was destroyed in a fire when he was injured). Obviously those later ones had black Gen II Redfield scopes (post 1968) + round safety + long bolt shrouds. Just a random historical factoid re M40 variations in the late 1960s...
(BTW, I took that close-up pic of Mawhinney's M40 at the USMC museum back in 2018. It's bolt has a short shroud circa 1966, but safety is the 1969 version. It was restored in 1996 by a retired USMC MOS 2112 I met a few years ago. Major Jim Land (ret.) donated an original M40 stock for that rifle).
This is not an original M40 bolt, but was refinished at PWS with the black oxide finish, same as what Remington used in the late 1960s.
It is from an early 1990's C-prefix rifle, and stamped as done on M40A1s. I recommend trying to mimic this finish on an M40 clone.
Last 4 of serial number engraved on bottom:
Digressing a bit (as I previously noted on your earlier post re M40 and SSA production volumes) there are really two drawings for M40s that Remington used for "Vietnam Era M40s". The first is the 1966 version of the drawing that made up the original M40 order by the USMC, but the drawings were slightly updated in 1968 and again in 1969 with more notable changes, which was also the final revision of the M40 blueprints.
The current/final M40 drawings that Remington maintained (before the recent bankruptcy...) were dated 1969, per the former sales manager for Remington Defense. (Hence the dust-up years ago re shape of the safeties on the SSA and Chuck Mawhinney rifles as Remington used their M40 drawings for those replicas - and the only drawings they maintained at the factory were the last approved ones, dated 1969...but of course customers were assuming the older 1966 configuration with the 'tombstone' shaped safety.)
Joe Poyner's review of the Remington archives shows 15 gov't orders/contracts for a total of 972 M40s delivered to various depts or Arsenals within the US gov't from the years 1966 to 1969. Here's the overview of the archives:.
M40 sniper rifles sold to the US gov't by year:
1966 = 714 (biggest contract was Boston Procurement District for 700 M40s - not specifically noted as to what branch, but this is clearly the original USMC rifle order. Small contract for 6 rifles each for COUSN Regional Financial District and NAVY SPT GRP Pacific)
1967 = 42 (biggest contract was Edgewood Arsenal, MD for 30 M40 rifles, followed by Frankford Arsenal, PA for 7 M40 rifles)
1968 = 81 (biggest contract was Military Air Command, Dover AFB in Delaware for 58 rifles, followed by Frankford Arsenal, PA for 9 rifles, and US Naval Weapons Center, China Lake, CA for 6 M40s)
1969 = 135 (biggest contract was again Boston Procurement District for 105 M40s- unclear from records who received these, but please note that Boston was used for the previous USMC procurement in 66'; and a separate order by US Navy Training Center in San Diego for 30 M40 rifles.)
TOTAL = 972 rifles
(All subsequent USMC orders were just the receiver and probably bolts, but not complete rifles as RTE/PWS was by then building the M40A1/3/5 rifles with the various prefix receivers, C, E, G, etc).
So one could say their were 2 variations of M40s that served USMC Scout Snipers in Vietnam, the initial 1966 variation w/ serialized green scopes + flat face safeties, and short bolt shrouds, etc. And in the later years perhaps a small number of 1969 production that were replacements for rifles lost, damaged or destroyed during the war (ie, for example, Carlos Hathcock's M40 that was destroyed in a fire when he was injured). Obviously those later ones had black Gen II Redfield scopes (post 1968) + round safety + long bolt shrouds. Just a random historical factoid re M40 variations in the late 1960s...
(BTW, I took that close-up pic of Mawhinney's M40 at the USMC museum back in 2018. It's bolt has a short shroud circa 1966, but safety is the 1969 version. It was restored in 1996 by a retired USMC MOS 2112 I met a few years ago. Major Jim Land (ret.) donated an original M40 stock for that rifle).
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