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Thread: Data on end of barrel blank?

  1. #1
    Boolit Grand Master
    rockrat's Avatar
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    Data on end of barrel blank?

    Wondering if this is considered the breech or muzzle end. Remember reading about this many years ago, but time is not friendly sometimes, just plain forgot.

  2. #2
    Boolit Grand Master

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    In rhe barrels I buy the marked end is the breech. You need to get this right as cut rifled barrels are slightly smaller at the muzzle end and reversing the tube can lead to poor accuracy.

  3. #3
    Boolit Master

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    Actually I have read that some makers stamp the big end so you can use it for the breech end, there is nothing in the cut rifling process that would make one end smaller than the other with consistently.

    Bill
    Both ends WHAT a player

  4. #4
    Boolit Grand Master leftiye's Avatar
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    Yup, but there may be microscopic burrs running in the direction the cutters were moving when they cut the rifling. This should be read as burrs laid over towards the muzzle.
    We need somebody/something to keep the government (cops and bureaucrats too) HONEST (by non government oversight).

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  5. #5
    Boolit Grand Master JIMinPHX's Avatar
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    I did not know that. From now on I'm going to slug both ends of a blank before using it.
    “an armed society is a polite society.”
    Robert A. Heinlein

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  6. #6
    Boolit Grand Master leftiye's Avatar
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    Running a patch from both ends should (no guarantee) tell you which way is which.
    We need somebody/something to keep the government (cops and bureaucrats too) HONEST (by non government oversight).

    Every "freedom" (latitude) given to government is a loophole in the rule of law. Every loophole in the rule of law is another hole in our freedom. When they even obey the law that is. Too often government seems to feel itself above the law.

    We forgot to take out the trash in 2012, but 2016 was a charm! YESSS!

  7. #7
    Boolit Master
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    Even the very inexpensive blanks I just used have a consistant taper. The machinist turned a brass plug that fit snugly in one end of the bores. It wouldn't come close to starting in the other end.

  8. #8
    Boolit Master

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    Quote Originally Posted by dubber123 View Post
    Even the very inexpensive blanks I just used have a consistant taper. The machinist turned a brass plug that fit snugly in one end of the bores. It wouldn't come close to starting in the other end.
    No rifling process other than maybe hammer forging creates a taper(and then only if you used a taper mandrel). When taper was desired in rifle barrels it was generally lapped in. Choke boring is used in some euro 22 target rifles, but they achieve it by leaving the muzzle end of the barrel blank larger at the muzzle, so when they button rifle the muzzle ends up a touch tighter.

    Cut rifling for example, the cutter completely traverses the bore and is retracted on the back stroke, it is fed out .0001 then cuts each groove, than another .0001.....the cutter is not moved while cutting the barrel. Button rifling the uniform outside dia blank has a button pulled through it's bore, then afterwards it is contoured(and then it is hand lapped if it is a premium grade bbl)....if it were contoured beforehand the muzzle end of the bore would be larger than the breech due to the "snake swallowing en egg" nature of button rifling.

    Many rifle barrel blanks are hand lapped, and the last 1" of the barrel is supposed to be cut off for final use, the breech 1" gets removed when you chamber the barrel.....this is because of the nature of the lapping process,they do not push the lap clear out of the muzzle end of the bbl so that portion is un lapped.

    Bill
    Both ends WHAT a player

  9. #9
    Boolit Grand Master

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    Call the bbl maker.

    Bill
    If it was easy, anybody could do it.

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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