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????Forcing Cone and Overbore????

Discussion in 'Uncategorized Threads' started by RidefastShootstraight, Sep 30, 2007.

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  1. RidefastShootstraight

    RidefastShootstraight TS Member

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    I owned a MX2000, 30 inch barrel .724 bore which I had the forcing cone lengthened and I loved the reduced recoil, now I have a MX2000 with 32 inch barrel of .735 bore, should I lengthen the forcing cone ? will it work just as well, and what does over bore do?

    thank you very much.

    T.S
     
  2. maclellan1911

    maclellan1911 TS Member

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    Good to hear it worked for you, How about pattern? any better. I have one member who pissed and moaned that there was no diff in recoil. When he went to the patern board he claims his patern is much more uniform and evenly spread???? he only shoots new STS light target.
     
  3. Hipshot 3

    Hipshot 3 TS Member

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    Sarge gives good info to consider. Generally you don't need BOTH an overbored barrel AND long cones. In an overbored[BACKBORED] gun you already have what you need. I had a DB-81 which I also had the cones extended on and experienced the same good results you did.
     
  4. phirel

    phirel TS Member

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    fred- Lengthening the cones does nothing more than change the angle of the forcing cone. This angle change does lengthen the cone very slightly. So little metal is removed that I doubt a safety issue is involved.

    Ron- How would a change in the angle of the forcing cone and a resulting lengthening of the cone by something like 0.1 inch flatten the pressure peak? The pressure curve has already begun to decrease before the wad base that seals the pressure in the hull/chamber reaches the forcing cone?

    Pat Ireland
     
  5. Hipshot 3

    Hipshot 3 TS Member

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    Pat.....Thats good advice, but the lengthening of the cones is[AND WILL] provide for a smoother transition of the pellets from the shell to the smaller barrel configeration and thus produce not only less recoil but a better pattern also.
     
  6. Cherokee Kid

    Cherokee Kid TS Member

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    Reduced recoil? Nonsense.
     
  7. ramorton

    ramorton TS Supporters TS Supporters

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    I have had this done before on a Perazzi MX2000RS by Tom Wilkinson. He does fine work, however, I found no real difference in the recoil. The pattern was enhanced somewhat regarding more pellets in the annular ring. I cannot tell any difference in the way it broke targets. I now have a Perazzi MX10RS, same gun, and from the factory it was set up with .736 I.D. .705 choke. .o31. This barrel seems to hit targets harder than my other gun with .742 I.D. and .708 choke for .034. It may very well be a waste of money. My old Perazzi from the factory was .725I.D. so that is the reason I had Tom do the work. It is like a lot of other suggestions in this sport, it is what makes you happy. I prefer correct stock fit over all the rest. Hope this helps, Roy
     
  8. RidefastShootstraight

    RidefastShootstraight TS Member

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    Thanks guys!

    I will shoot the gun as it is for a while and if I run out of things to tinker with I will probably get it done and report back the results.

    T.S
     
  9. phirel

    phirel TS Member

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    T.S.- That is not a bad idea. I can report back my results with changing the angle of the forcing cones-- The work did not do anything bad to my gun. I could not really demonstrate any improvement but the pattern was not made worse by lengthening the forcing cone. And, although I have not found a way to measure perceived recoil, there was no change in felt recoil that I could detect.

    If I were to buy a new gun, probably I would send it to Tom W. and ask him to do whatever he though best to the barrel. I am convinced this would not hurt the gun at all and it might help.

    Pat Ireland
     
  10. hmb

    hmb Well-Known Member

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    The answer to the question requires a simple scientific solution. Backboring and forcing cone work remove metal from the barrel. This reduces the weight of the gun, which increases recoil.
    For a more detailed analysis please feel free to contact Sir I. Newton, at Iamanewton.com. HMB
     
  11. Neil Winston

    Neil Winston Well-Known Member

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    ...if the resulting shot-speed remains unchanged after the work, the forcing-cone aspect of which I may get to test this week.

    Neil
     
  12. IM390

    IM390 Member

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    From my reading, a longer forcing cone allows the crimp to open easier allowing everything inside to come out smoother without banging into one another so much. The back bored barrel also allows the payload and wad an easier trip down the barrel without interference. They are suppose to work together to improve the quality of the load. Quality means better pattern, velocity and reduction of pellet deformation. I have a 391 Urika Optima, which has both and it does not have as much recoil as my older 391, using the same load. The pattern is one step wider than in the 391. All the other chokes appear similar to each other without substantial separation as one might expect without viewing the quarter chokes in between.
     
  13. bobby ward

    bobby ward Member

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    Fred,

    If you contact ANY manufacturer, they will advise you against any after market barrel work based on liability issues. Browning even voids the factory warranty if you alter one of their guns from factory specs in any way. I had a friend send in his sporting clays gun that had Speers release triggers in it and Browning sent it back to him untouched and said his serial number was now on file with the warranty voided. Nice people huh?

    Barrel work if done by a competent barrel smith can do wonders for the performance. Tom Wilkinson is probably the most well known right now, but Eyester out of Indiana I believe does good work as well. Some people think they are going to send their gun off and it will come back with zero recoil. What you will experience more likely is less recoil fatigue over a long day of shooting and better and more consistent patterns.
     
  14. JerryP

    JerryP Active Member

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    Do Wilkinson or Eyster offer any guarantee on their work, any proof of enhancement? Or do I just accept on faith that they did improve my barrel. I know from experience what it takes to determine barrel performance and I just don't see these guys putting in that much time testing, it would be cost prohibitive. So, with that in mind, I'm guessing they do a set routine for each brand of barrel and you get what you get. Which may be nothing since no one ever tests the results.
     
  15. fearlessfain

    fearlessfain TS Member

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    do not spend money on your gun to make worth less. the factories know more than any so callad barrelsmiths.
     
  16. Neil Winston

    Neil Winston Well-Known Member

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    Oh how quickly they forget, Jerry. Someone does do some testing. Here's one.

    I have subsequently found an error in this, namely that the unmodified tube is not an "8" as the post says - and which raised so many questions - is was, as I look at it now, a "6" which, with the backbore, is the same as an "8" more or less, that's what I must have been thinking. This change does not change the pellet counts, percentages, comparisons, or conclusions one whit, however.

    Neil
     
  17. Neil Winston

    Neil Winston Well-Known Member

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    And here's yet another.
     
  18. bgf

    bgf Active Member

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    Question????

    If all this after market barrel work did wonderful things to a shotgun's performance...don't you think the manufactures would jump on it as a "New and Improved" way to sell new guns? The money that the factories put into testing is a formidable sum. Don't ya think?

    Bernie
     
  19. Hap MecTweaks

    Hap MecTweaks Well-Known Member

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    If there's a secret to all the aftermarket barrel work, I'd wager it lies in making the barrel internals much smoother. The smoother it measures in REMS, the more loads it shoots decently, including reloads. Theres another shotgun anomaly that I feel smoothness plays a big part in also but I won't go into that. Neil can tell us from shotgunning history what the old time tests for shotguns were mostly about at that time. Hap
     
  20. miketmx

    miketmx Well-Known Member

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    Hap, I thought REMs stood for 'rapid eye movement' and was an indicator for deep sleep when a Dr. is testing for sleep apnea. Anyhow, I remember some older threads about the magical Herb Orre chokes and some of the consensus was that Herb used some pretty primitive hand reamers by today's standards but he was able to open up a Model 12 so that it shot a better pattern for 16 yards when compared to the probably overchoked factory original choke.
     
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