1. Attention: We have put together a thread with tips and a tutorial video to help with using the new software. Please take a moment to check out the thread here: Trapshooters.com Tutorial & Help Video.
    Dismiss Notice

back bore / forcing cone

Discussion in 'Gunsmithing' started by nobu, Nov 14, 2016.

  1. nobu

    nobu TS Member

    Joined:
    Feb 14, 2014
    Messages:
    26
    Location:
    Denver
    I think I know what back boring is but is that related in any way to forcing cones?
     
  2. Eddiefromoverlook

    Eddiefromoverlook Active Member

    Joined:
    Nov 30, 2006
    Messages:
    418
    A forcing cone is the area of transition between the chamber of the barrel and the bore. It is also the area of transition between the bore and the choke. Both are technically forcing cones

    Back Boring is the opening of the barrels original ID which also affects choke performance.
     
    Last edited: Nov 14, 2016
    2llc and Charlie Becknell thanked this.
  3. smokintom

    smokintom Well-Known Member

    Joined:
    Dec 28, 2010
    Messages:
    3,048
    Location:
    Ohio
    Lengthen forcing cones have nothing to do with felt recoil if that's what you're looking for.
     
    2llc and Neil Winston thanked this.
  4. nobu

    nobu TS Member

    Joined:
    Feb 14, 2014
    Messages:
    26
    Location:
    Denver
    Thanks for the replies. I never mentioned felt recoil but that is exactly what I was aiming for because I was told that both back boring and/or lengthening the forcing cones was a way of reducing felt recoil. I'm going to post another subject about my recoil persuit. Thanks.
     
  5. hmb

    hmb Well-Known Member

    Joined:
    Jan 29, 1998
    Messages:
    9,621
    When you change the specifications of the barrel you will affect the felt recoil. HMB
     
    gailmk67 and WesleyB thanked this.
  6. smokintom

    smokintom Well-Known Member

    Joined:
    Dec 28, 2010
    Messages:
    3,048
    Location:
    Ohio
    The concept of lengthened forcing cones was to reduce shot deformation as the shot was transferred from the hull to the bore. That's it
     
    2llc, Stl Flyn and Neil Winston thanked this.
  7. Eddiefromoverlook

    Eddiefromoverlook Active Member

    Joined:
    Nov 30, 2006
    Messages:
    418
    I disagree smokintom,

    Removing and lengthening the forcing cones does reduce felt recoil. You are correct stating the original
    concept of lengthened forcing was to reduce pellet deformation but the forcing cone alteration also reduces felt recoil.


    The biggest reduction of recoil comes from increasing the inside diameter of the barrel through back-boring.

    Eddie

     
    Last edited: Nov 17, 2016
    gailmk67 and leadingedge thanked this.
  8. 3200-man-2

    3200-man-2 Member

    Joined:
    Nov 23, 2013
    Messages:
    204
    But Eddie ? Wouldn't that be Over-Boring a barrel as Back Boring is when , just the area of where a choke tube is , is swedged-out to a larger diameter ?
     
  9. Eddiefromoverlook

    Eddiefromoverlook Active Member

    Joined:
    Nov 30, 2006
    Messages:
    418
    3200-man-2, But Eddie ? Wouldn't that be Over-Boring a barrel as Back Boring is when , just the area of where a choke tube is , is swedged-out to a larger diameter ?

    I've had three OU's, an auto and a SXS ( with dedicated chokes) back bored and their choke areas were never touched .

    Can you explain what advantage or benefit that altering the choke tube area would produce?

    Eddie
     
    Last edited: Nov 18, 2016
  10. jlmccuan

    jlmccuan Active Member

    Joined:
    Aug 16, 2015
    Messages:
    154
    Location:
    Southern Illinois
    Opening just the area behind the choke for a few inches is normally called jug choking. Backboring without touching the choke area would increase the constriction of the choke by the amount of the backbore unless tapered backboring is used. I don't know if anyone is still doing that. Overboring is what manufacturers did to sell some sizzle on their new guns when backboring was the cure all for patterning, reducing recoil and various other claims. This resulted in the overall diameter of the barrels being larger and increasing the weight of the barrel sets as compared to that manufacturers pre-overbored barrels. Just compare a set of American Browning 325 32" barrels to the European non-overbored 32" barrels. I had a set of pre-overbored 32" barrels backbored .020" and they were lighter than the 28" overbored barrel set.
     
  11. Two Dogs

    Two Dogs Banned User Banned

    Joined:
    Jan 29, 1998
    Messages:
    1,576
    Smokintom has no idea...
     
  12. Cowboy Rick

    Cowboy Rick Active Member

    Joined:
    Jul 13, 2016
    Messages:
    314
    I agree with Eddie.... backboreing DOES reduce felt recoil......as most recoil
    occutes when the shot first leaves the hull.
     
  13. smokintom

    smokintom Well-Known Member

    Joined:
    Dec 28, 2010
    Messages:
    3,048
    Location:
    Ohio
    So your saying take two identical guns. One with a standard forcing cone and one with a lengthened forcing cone firing identical shells that the one with the long forcing cone will kick less ??? Come to Ohio there`s a bridge down the road I would like to sell you.
     
    Last edited: Nov 18, 2016
  14. hmb

    hmb Well-Known Member

    Joined:
    Jan 29, 1998
    Messages:
    9,621
    When you back bore a barrel or when you lengthen the forcing cone of a barrel you remove metal from the barrel.
    When you remove metal from the barrel you reduce the weight of the gun. When you lower the weight of a gun
    the recoil increases. You can't argue with recoil science. HMB
     
    gailmk67, Rebel Sympathy and Neil Winston thanked this.
  15. sasquach

    sasquach Active Member

    Joined:
    Jan 29, 1998
    Messages:
    296
    Newton's rules apply to everything but shotguns.
     
  16. hmb

    hmb Well-Known Member

    Joined:
    Jan 29, 1998
    Messages:
    9,621
    Were Newton's barrels back bored? HMB
     
    Jason Stagner thanked this.
  17. fast gun

    fast gun Active Member

    Joined:
    Sep 25, 2012
    Messages:
    708
    Find a copy of Barrel modifications by Tom Roster that should answer your Questions.
     
  18. Jason Stagner

    Jason Stagner Member

    Joined:
    Apr 30, 2015
    Messages:
    59
    Lol! HMB, that was a good one. Thanks for the laugh!
     
  19. smokintom

    smokintom Well-Known Member

    Joined:
    Dec 28, 2010
    Messages:
    3,048
    Location:
    Ohio
    Newton only owned rifles. I don't think he back bored them.
     
  20. 3200-man-2

    3200-man-2 Member

    Joined:
    Nov 23, 2013
    Messages:
    204
    If Over-sizing the bore of a shotgun wasn't beneficial , why are most all manufactures offering over standard bored barrels ? I read where Newton loves them ......:2angel: