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Thread: Number of grooves?

  1. #1
    Boolit Master andym79's Avatar
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    Number of grooves?

    Hi guys I am sure this question has been asked before but are there any advantages or disadvantages between 3, 4, 5 or 6 groove barrels when shooting cast.

    My gut says more grooves may improve accuracy but increase fouling, is there any truth in that?

  2. #2
    Boolit Master


    Larry Gibson's Avatar
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    In my opinion based on experience I prefer 3 or 4 up through 8mm. From 35 through 45 cal I prefer 6. They should provide 35 to 40% bore surface. Groove depth should be minimum of .004 to .005 max.
    Larry Gibson

    “Deficient observation is merely a form of ignorance and responsible for the many morbid notions and foolish ideas prevailing.”
    ― Nikola Tesla

  3. #3
    I've had very good results shooting cast bullets from both 4 and 6 groove barrels.

    Also hd one WWI Springfield 03A3 that shot well with a 2 groove barrel.

  4. #4
    Boolit Master Oklahoma Rebel's Avatar
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    what about the 250B and 285C accurate design, they are 9.3 cal and are GCrnfp with one lube groove that's deeper than what you see on multi groove boolits. for 2000-2200fps would a hard lube like carnauba red be best or would their carnauba blue be ok, because I don't have a lube heater. thanks a lot-Travis
    Norinco SKS
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  5. #5
    Boolit Master
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    The more GG bands increases bearing surface obturating IMO
    Name:  375084-37584_156g-176g-197g-218g-238g-259g-280g-301g-322g.gif
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Size:  5.9 KB Ideal 37584 - note the small base width
    Regards
    John

  6. #6
    Boolit Master




    Scharfschuetze's Avatar
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    I've had good accuracy with rifling from two, three, four, five and six groove barrels. I think that the twist rate and the bullet fit and quality (jacketed or cast) is far more important than the number of grooves. Other than in 22 rim fires, I've had no experience with lead bullets with Marlin's Micro Groove rifling, so I can't comment on that genre of barrel.

    Over the years I've heard many a discussion over the topic at rifle matches. In summary, winners have used any number of grooves in their barrels to win and it isn't always consistent from match to match or year to year.
    Keep your powder dry,

    Scharf

  7. #7
    Boolit Master
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    How could more GG bands increase obturation when every groove represents less contact between the bullet and the bottom of the groove?

  8. #8
    Boolit Master Oklahoma Rebel's Avatar
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    oh, that's my bad, I rushed through yyour post and thought you were talking about boolits, in gunsmithing there is a special section just for talk about barrels. me, I would prefer 3-4 for cast, but I don't have the gunsmithing knowleddge to back that up! good luck!-Travis
    Norinco SKS
    mosin nagant est 1937
    S&W 15-2 combat masterpiece
    Remington 597 22lr w/30 rnd clip
    12ga NEF single shot
    heritage 22lr/22mag

  9. #9
    I only cast for pistols but have not noticed a difference.

  10. #10
    Boolit Master
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    Quote Originally Posted by Scharfschuetze View Post
    . I've had no experience with lead bullets with Marlin's Micro Groove rifling, so I can't comment on that genre of barrel.
    Marlins Micro groove barrels shoot cast just fine, contrary to what is said. I have great success and accuracy with them.

  11. #11
    Boolit Master RU shooter's Avatar
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    A very wise and experienced dearly departed member here named Felix always said go with odd numbered be it 3,5,7 and so on . He was a BR guy , I doubt for regular stuff there's a measurable difference between odd and even
    If you find yourself in a fair fight, your tactics suck!

  12. #12
    Boolit Master




    Scharfschuetze's Avatar
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    It's interesting to look at what the various militaries opted for regarding the number of grooves with the advent of rifled military rifles. The first world armies invested a lot of time and money into adopting accurate rifles.

    With the advent of rifled muskets in the US Military, 3 groove barrels were the norm. That remained the standard throughout the Trapdoor series of rifles in both 50/70 and 45/70. A good Trapdoor will shoot very well to very long range. With the adoption of the Krag and the following Springfield, Garand, M14, M16 and the M4, the rifling was/is all even numbered, generally 4 groove. There are exceptions I'm sure, but an even number is the standard. The Model of 1917 (US Enfield) used much of the tooling for the British P14 Rifle and thus had 5 groove Enfield rifling.

    If my memory is correct, the British also used 3 groove rifling in their muzzle loading rifles and later a 7 groove "Henry" style of rifling in the Martini Henry. The follow on Lee-Metford in 303 British used a similar 7 groove rifling and that is now well known as "Metford" rifling. As Cordite eroded that form quickly, they adopted the 5 groove Enfield style of rifling and the rifle series became know as the Lee Enfield. With the adoption of the 7.62 NATO and later 5.56 NATO rifles, I believe that they are back to even numbers of grooves and lands.

    The Germans? Even numbers of lands and grooves if my Mausers are any indication of Peter and Paul's preference. With the G3, they went with a Polygonal style of rifling, but they are now back to a conventional form with 6 grooves and lands in their G36 rifles.

    The Japanese initially had conventional even grooves and lands for their Type 38 rifle's in 6.5 calibre. With the adoption of the Type 99 in 7.7 calibre, they adopted a Metford type rifling with chrome lined bore. I have no idea what they are using in their current rifles, the Type 64 (7.62) and the Type 89 (5.56).
    Last edited by Scharfschuetze; 08-01-2017 at 12:41 PM.
    Keep your powder dry,

    Scharf

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Abbreviations used in Reloading

BP Bronze Point IMR Improved Military Rifle PTD Pointed
BR Bench Rest M Magnum RN Round Nose
BT Boat Tail PL Power-Lokt SP Soft Point
C Compressed Charge PR Primer SPCL Soft Point "Core-Lokt"
HP Hollow Point PSPCL Pointed Soft Point "Core Lokt" C.O.L. Cartridge Overall Length
PSP Pointed Soft Point Spz Spitzer Point SBT Spitzer Boat Tail
LRN Lead Round Nose LWC Lead Wad Cutter LSWC Lead Semi Wad Cutter
GC Gas Check