Unconventional M1 Garand barrel?

Discussion in 'General Military Arms & History Forum' started by Elvio, Apr 30, 2009.

  1. Elvio

    Elvio New Member

    Jan 6, 2006
    I'm at the end of my rope . I have an SA M1 barrel with standard markings but atypical rifling...that is to say, that instead of the "normal" 1 turn in 10" rifling this barrel has a 1 turn in 12" twist. I've measured it over and over...from the muzzle, from the breech, it still flags as a 1 in 12 and no-one seems to know where this originated or what program it might have belonged to. It isn't like a 1 in 12 is broached by accident; these things are planned. Any insight to this little thing? Was there only one produced? I doubt it...why were they made? The date stamped is 7/64...any information would appreciated...
  2. islenos

    islenos New Member

    Mar 16, 2004
    West Texas
    In 1964-65 Springfield Armory was contracted to make barrels in 7.62x51 with a twist of 1:12. That is the only barrels in 1:12 twist that I know of.

  3. Elvio

    Elvio New Member

    Jan 6, 2006
    These barrels were marked as 7.62 x 51 though, right? Besides, I've fired this many times and it is a 30-06...it is a CMP delibvered firearm. It can't be rechambered because a .308 (7.62 x 51) has a greater case base diameter than the 30-06.
    Last edited: Apr 30, 2009
  4. islenos

    islenos New Member

    Mar 16, 2004
    West Texas
    Yea, they would be marked 7.62 NATO but to my knowledge those were the only ones that were made with a 1:12 twist.

    The last M1 was built in 1957, your barrel looks like a 1965, so your rifle has been rebuilt with a new barrel.

    Possible after making the NATO barrels for the Navy, Springfield Armory might have made some extra 30:06 barrel with the 1:12 set up before shutting the doors. Since you replacement barrel falls in the time frame, this might be why it's a 1:12.
    Last edited: Apr 30, 2009
  5. Elvio

    Elvio New Member

    Jan 6, 2006
    There is always that possibility.
  6. islenos

    islenos New Member

    Mar 16, 2004
    West Texas
    BTW welcome to the board, hope you stick around and I'll keep looking through my books and see if I can come up with any more information.
  7. Elvio

    Elvio New Member

    Jan 6, 2006
    FWIW...This is what a collector offered up...

    That is a 1954 SA barrel, if you look very closely at the top of the "6" it is flat and not rounded which makes it a pooprly stamped "5" (could have been a worn stamp or a poor stamping operator) the F-Series drawing number and MD 41 heat lot code along with the uneven DAS stamp is common for SA rifles and especially from the 1954 time period (by Dec 1954 they where on MD 45 heat lot code). There are plenty of examples of the drawing number and other numbers being offset, Duff has an example of one on page 95 of his Post War Garand book. I have examples of offset, double stampings and poorly marked or partially obscured drawing number, date and heat lot codes all these barrels are on CMP purchased rifles which I wouldn't think would be using faked barrels.

    During this mid 1954 time period they where working on the examples of the T44E4 (later to become the M14 rifle) so it is possible the barrel rifling was cut on a machine that was being used to make T44E4 barrels, as this was to be an automatic rifle chambered for the 7.62 Nato round the barrel parameter was changed to 4 groove and 1:12" twist vice the 1:10" twist normally found on the M1 Garand. As with most barrels manufactured the final outside contour cuts would not have been made until the rifling was completed to maintain alignment of the bore and it would be easy to have a 1:12 rifled blank put on the line to be final contoured as a Garand barrel rather than as a T44E4 barrel. Mistakes happen even at Springfield Armory, they where making 2 types of rifles at the same time.

    You have a unique barrel which I would bet is 99% original and not a fake, enjoy it.

  8. JLA

    JLA Well-Known Member

    Feb 26, 2007
    Heart Of Texas
    plus it should shoot the lighter bullets better. In a sense you have an m-1 garand that with properly assembled handloads could propel a 110 gr. hp at a wiley coyote at nearly 3500 fps;), with less chance of bullet failure do to the light bullets in a barrel with too fast twist rate... That could be fun...:D
  9. JohnM

    JohnM New Member

    Jul 23, 2009
    Tulsa, Oklahoma
    Well, I have another M1 with a SA barrel dated 11 65 and it's also 1 in 12. I have been shooting this rifle sporadically at the monthly semi auto vintage rifle competition for over a year at the Tulsa Red Castle Gun Club, and haven't been very pleased with the mil surplus ammo that's on the market these days. I shot 180 grain Federal during the first match and it actually resulted in the best groups so far, but the guys at the club say I shouldn't use a round this heavy due to over pressure on the receiver. I'm going to start reloading in a few weeks and actually started looking for info on this barrel today because I'v heard they did re-barrel a few for Viet Nam, but I haven't heard why. I was wondering if they had some special plans for these weapons since it's my understanding the M1 Garand was basically replaced by the M14 and M16 by this time. Also, the bore is extremely shinny which makes me wonder if it wasn't polished. It shoots better than my 03-A3 with any ammo.

    So, I'm wondering if will shoot a 125 grain bullet with good accuracy as has been suggested earlier in this thread. I tried 125 grain in handloads nearly fifty years ago hunting woodchucks on our dairly farm in Western NY State but didn't have very good results, whereas the ball ammo available at the time was pretty accurate.

    I'll take a couple phots and upload a picture of the barrel markings if there's any interest.
  10. Elvio

    Elvio New Member

    Jan 6, 2006
    It isn't the bullet that's too heavy. It depends on the powder charge's burning rate. The M1 was originally designed for the M1 round which was available and being fired in the 03 and 17; after which it was changed to the M2 round (155gr) to maintain uniformity with machine-gun supplys. This round (M1) carried, IIRC, a 172 or 175 grain slug. That being said, the powders used for the Garand is a medium burn powder...and has a burning curve which is suitable for the rifle. Many commercial ammos have slower burning powders and therefore have a different curve which could potentially damage the op rod because of the amount (rate, pressure) which is transferred to the gas cylinder. In using commercial ammo make sure it is designated as suitable for the M1 Garand.
  11. JohnM

    JohnM New Member

    Jul 23, 2009
    Tulsa, Oklahoma
    Thanks Elvio, for the powder burn info and have you heard anything else about the 1 in 12 twist on your Garand's barrel? I think the picture of your rifle shows a 64 and not a 54.
  12. Elvio

    Elvio New Member

    Jan 6, 2006
    Nothing further on this barrel from anyone...in fact, not on this forum, I was challenged as to whether or not I knew how to measure the twist because they were told, or heard, that M1's were ALL 30-06 and/or 1 in 10" twist...some people take everything as gospel without ever researching the facts...look at how many people voted for Obama!
    The barrel IS a 54...it was cross confirmed by the heat lot number. I originally also thought it was a 64.
  13. Shortround

    Shortround New Member

    Jul 24, 2009
    Avilla, Arkansas
    All M1's were not chambered for .30-06.
    In 1968, while at boot camp, all the M-1's used for weapons qualifications were chambered for .308/7.62mm.
    I thought that was rather strange since every M-1 I had shot prior to that time was in .30-06(numerous range firings with my father when he was in the National Guard and also our ROTC weapons).
    While in the Navy, I came across the same .308/7.62mm chambering numerous times. The Coast Guard even had some at least up until the '77 time frame. This is Bruce speaking/thinking out loud now,"I think this was/may have been a Naval thing. All of our competition "service rifle" weapons were chambered for .308/7.62mm, (M-1 and M-14). Since our close quarters weapons were M-1911's and Thompsons firing the .45 ACP, it made since to have the "heavier" M-1, M-14, and M-60 LMG all firing compatible ammo." When the weapons transition to the AR-15/M-16M-9 took place, I'm not sure. Find you an old retired GMG (Gunners Mate Gun) and he could probably give you some greater insight.
    Remember that the Army was the sole small arms procurment agency for all services branches for many, many years.
    You have yourself an interesting find. Keep us posted.

    Shortround out
  14. Shortround

    Shortround New Member

    Jul 24, 2009
    Avilla, Arkansas
    Adding another question mark, I came across this.

    From: bartbob@aol.com (Bartbob)
    Newsgroups: rec.guns
    Subject: Re: Garand Navy 308 Question
    Date: 10 Mar 1999 10:22:13 -0500

    I'm really surprized at all the incorrect information posted regarding these US
    Navy M1 Garands in 7.62mm NATO. If anybody chooses to talk with anyone
    directly involved in the USN's NATO Garand program in the middle 1960s, here's
    what they will learn.

    In the early 1960s, the USN Small Arms Marksmanship Unit in San Diego (located
    at what used to be Camp Elliot south of Miramar NAS) wanted to do two things.
    One was to upgrade all their rifles used for training recruits at USNTC San
    Diego to use the 7.62mm NATO round. The other was to upgrade all their match
    grade service rifles to the same cartridge. Virtually all of this was
    spearheaded by Charles Frazier; a retired Navy chief petty officer who went to
    work as a civil service employee of the US Navy. Charlie ran the Match
    Conditioning Unit where work on both rifles and pistols was as good as it got.

    Someone suggested a chamber insert. Several were made and the project came up
    with what seemed to work well. But after a long period of testing and use,
    and several of these inserts comming out with the empty case, this idea was
    quickly abandoned. There were fewer problems by just using a 7.62mm NATO round
    in an unmodified .30-06 service chamber.

    The US Navy contacted Springfield Armory in Mass. to make a batch of barrels on
    the same machines used to make them for the 30 caliber Garands. The only
    differences were the bore was rifled 1:12 (30 caliber barrels were 1:10) and
    chamber them for the 7.62mm NATO round. All these barrels were broach cut
    rifled. They were all stamped "7.62 NATO) on their right side just in front of
    the tenon shoulder and this is visible when the op rod is pulled back. They
    were also date stamped in 1964 or 1965; the year they were made. And they were
    all chrome-moly material; none were made in stainless steel.

    At the USN Small Arms Match Conditioning Unit at the same place as the Training
    Unit, all these M1 7.62mm barrels were measured with a Sheffield air gage for
    groove diameter uniformity. Those with the smallest groove diameters with most
    uniformity were set aside for use in the match grade M1s. About 40% of about
    3000 or so barrels met this criteria. All the rest were set aside for use in
    standard training rifles. The last two numbers of the groove diameter was
    scribed on the barrel. If the groove diameter was .3078 inch, "78" was put on
    the barrel. Groove diameters ranged from .3077- to .3082-inch. Those at or
    under .3079-inch were considered match-grade. Most interesting was how uniform
    in groove diameters these broach-cut barrels were.

    As the M1s were first being converted, it was found that in test firing, the
    gas supplied to the op rod to function the rifle was not quite enough with the
    standard 30 caliber barrels's gas port diameter. These holes had to be opened
    up a few thousandths of an inch. It was a standard operating procedure that
    when a new 7.62mm M1 barrel was pulled from the box to go in a rifle, the gas
    port was drilled out. The second thing that was done was to knurl the barrel
    where the lower band went so it would be a tighter fit.

    I've watched the shop crew rebarrel many 30 caliber M1s to service and match
    grade 7.62mm NATO Garands. It doesn't take very long to drill and knurl the
    barrel, strip the barrel group of an M1, put the barreled action in the
    barreling machine, replace the barrel, then put everything back together. The
    big difference is what they did to the match grade ones in fitting all the
    parts and using the select-grade barrels for them. Especially in how the gas
    cylinder and op rod were fitted as well as epoxy bedding the receiver with the
    barrel set in the right thickness of spacer on the stock's front end to get the
    right amount of pull-down pressure when the lower band was on the ferrule.

    They didn't stamp the receiver with any new markings. Nor did they mark
    anything else special with either the service or match grade M1s they
    converted. But there was one exception. Anybody who's actually used on of the
    match grade ones has noted the color mark on the gas cylinder lock ring; they
    were color coded as to how they clocked up tight on the barrel against the gas

    Each grade, service or match, was given a Mark and Mod designation; I don't
    remember what they were.

    Some interesting things about these M1s. Four of them were used in the late
    1960s by a USN team to beat the best bolt gun team in the USA at a long range
    match. Match-grade M1 service rifles from the USN SAMCU are the only service
    rifles ever used by anybody making the US Palma Team; nobody's ever made the US
    Palma Team using an M14 (for readers thinking the M14 or M1A is an excellent
    long-range rifle...). In machine rest tests, the USN M1s shot about 30% more
    accurate than those from the US Army or US Marine Corps marksmanship units.

    An interesting thing about these match-grade 7.62 Garands. The most accurate
    of all of them were built by a former USN Pistol Team member. He shot pistol
    for many years and was pretty good at it. He was also on Ford Island in Pearl
    Harbor on the morning of Dec. 7, 1941 as a young 3rd class petty officer. Two
    years later, he was promoted to Chief Petty Officer. When he retired from the
    USN in the late '50s, he went to work as a mechanic for the government and soon
    ended up at the USN SAMCU. He worked very close with Charlie Frazier to learn
    what really was needed to make the M1 Garand shoot virtually as good as the
    best bolt action match rifles of the day. His name is Don "Mac" McCoy. Still
    alive and well in San Diego.

    Sometime in the 1970s, there had been enough problems with people trying to
    insert a clip of 30 caliber ammo into a 308 M1 and having the rounds not
    chamber. The USN designed a white, plastic like insert that went in the
    receiver to prevent a clip of 30 caliber ammo being put in.

    Of course, it was also not cool for someone going to a match at Camp Elliot in
    this era with a 30 claiber M1 and not knowing this, then drawing 7.62mm ammo to
    shoot. After a dozen or so empty cases laying nearby were observed to not have
    any shoulder on them, the user oft times didn't get concerned at all. In fact,
    a couple of folks shot all 50 or 60 record shots this way and didn't even know

    By about 1973, all the match-grade 7.62mm NATO Garand barrels had been used up.
    There were a few service-grade barrels left but they were used in rebarreling
    shot-out NATO Garands of USN Rifle Team members until they were gone by the
    early 1980s.
  15. JohnM

    JohnM New Member

    Jul 23, 2009
    Tulsa, Oklahoma
    Thank you bartbob for all the info. It's extremely interesting!

    If "Broach cut" riflings means the cut slopes from the bottom of the groove to the top of the land, than that's what's on my M1. To put it another way, these aren't the evenly channeled grooves and square cut lands found in most barrels.

    I've uploaded a picture and here is was it says if it's hard to see.

    SA 6535448 11 65 BU27 Then, a sign shaped a little like the letter k, and next a capital letter M and a stamp that goes into the metal and almost looks like an upside down M is in it.

    The back of the receiver is marked: CAL 30 M1

    Does anyone have any thoughts on this configuration?

    Attached Files:

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