Page 1 of 2 12 LastLast
Results 1 to 20 of 27

Thread: Changing a Shotgun's P.O.I.

  1. #1
    Join Date
    Dec 2007
    Location
    The Salt
    Posts
    3,751

    Default Changing a Shotgun's P.O.I.

    Anyone ever filed a choke to change the POI?
    I shoot 20ga SxS as my primary turkey gun, no problems for the last 7 years with the POI until recently. It accepts thin wall chokes and I lost my one full so was finally able to get replacements made. Now the right barrel is shooting 6” to the right at 25 and 5 inch to the left on the left barrel. Figured it was the chokes but I have had several people say it’s due to the newer TSS loads. Which would make sense being it’s dead on with regular high brass dove loads. The only somewhat common solution I have found is to shave about 1/100th of an inch at a time off the choke in the direction to move the pattern. Thoughts?
    Quote Originally Posted by Glenn View Post
    I'll shoot over a kids head in a blind or long gun one on a turkey in a heart beat. You want to kill stuff around me you gonna earn it.

  2. #2
    Join Date
    Nov 2005
    Location
    Fort Kickass
    Posts
    50,993

    Default

    Following.
    "Rivers and the inhabitants of the watery elements are for wise men to contemplate and for fools to pass by without consideration" -Izaak Walton

  3. #3
    Join Date
    Dec 2008
    Location
    Sc
    Posts
    1,353

    Default

    Different loads will pattern different. My m2 20ga was a good bit high and right with my turkey loads. I changed the shims to bring it back on target. Make sure if you make a change you shoot the same shell.
    I don't belive in miracles, I rely on them.

  4. #4
    Join Date
    Dec 2007
    Location
    The Salt
    Posts
    3,751

    Default

    I've got the right load for it, just now have to figure out how to get it back on target. Guess i'm lucky I can change choke tubes if I screw it up.
    Quote Originally Posted by Glenn View Post
    I'll shoot over a kids head in a blind or long gun one on a turkey in a heart beat. You want to kill stuff around me you gonna earn it.

  5. #5
    Join Date
    Feb 2003
    Location
    North Kackalacky
    Posts
    3,473

    Default

    There is information related to filing a choke on a SxS on GobblerNation. His handle is poorcountypreacher.

    ETA link:

    https://www.gobblernation.com/phpBB3...eacher#p202837
    Last edited by gooseaholic; 03-25-2021 at 05:11 PM.
    Vegetarian: Native American for Piss Poor Hunter

  6. #6
    Join Date
    Dec 2002
    Location
    upstate, sc
    Posts
    3,286

    Default

    Rabbit hole I’m not going down. I’d pull out my first 870 and start shooting Copper plated 4s again like I did 30 years ago and piled up turkeys before I knew about all this other bullshit.
    \"We say grace and we say maam, if you ain\'t into that, we don\'t give a damn.\" HW Jr.

  7. #7
    Join Date
    Mar 2002
    Location
    Sullivan\'s Island
    Posts
    12,865

    Default

    When choke tubes first became popular, I was working in a machine shop. We brought in our barrels and swaged, bored and threaded them to accept tubes that we made on a CNC lathe. We made the tubes with undersized bores, pattern tested them and bored them out to get good patterns. One of the most interesting things I learned in that process was that the changes weren't necessarily linear. You could pattern a tube, skin .005" out of it and it might throw a tighter pattern. Skin another .005" and it might open up considerably. It was like there was some separate metric that we didn't well understand, like maybe a harmonic, cyclic pattern. It could have just been voodoo or some other dark magic.

    I'm skeptical about the idea of predictably adjusting the POI, and simultaneously keeping the pattern, of a tube by asymmetrically grinding metal off, especially when you've already proven it is affected by different shot loads. But what do you have to lose? Crank up the Dremel. You might get lucky. Worst case is that you'll have to go buy another tube and find the right load.

    If you discuss this with a gunsmith or machinist, it's customary to talk about sizes in thousands of an inch. 1/100th of an inch is 10 thousandths and that's a lot when you're talking about choke diameters. A piece of typing paper is about 3 thousandths. Rolling papers are about one thousandth. (.001)

  8. #8
    Join Date
    Nov 2009
    Location
    Spartanburg
    Posts
    1,690

    Default

    I put an adjustable sight on one that was shooting 6" high, but it only had one barrel. I think it was the flight control wad in those Fed. heavyweight 7s ?

  9. #9
    Join Date
    Nov 2008
    Location
    Scumter
    Posts
    21,805

    Default

    Who did the thin wall chokes?

    Sent from my SM-G970U using Tapatalk
    [SIGPIC][/SIGPIC]
    Delta in a nutshell: Breeding grounds + small wetlands + big blocks of grass cover + predator removal + nesting structures + enough money to do the job= plenty of ducks to keep everyone smiling!

    "For those that will fight for it...FREEDOM...has a flavor the protected shall never know."
    -L/Cpl Edwin L. "Tim" Craft

  10. #10
    Join Date
    Dec 2006
    Location
    Spartanburg
    Posts
    6,297

    Default

    Briley did some for me in a 1100 light 20.

  11. #11
    Join Date
    Mar 2002
    Location
    'Down in the Holler', SC
    Posts
    14,554

    Default

    Quote Originally Posted by gooseaholic View Post
    There is information related to filing a choke on a SxS on GobblerNation. His handle is poorcountypreacher.

    ETA link:

    https://www.gobblernation.com/phpBB3...eacher#p202837
    Thanks for that link. I had never heard of using that procedure before, although, undoubtedly it results in needing a different set of chokes for each favorite load. But that may not be a bad idea to have a well adjusted shotgun.
    .
    Foothills Golden Retriever Rescue
    .
    "Keep your powder dry, Boys!"
    ~ George Washington

    "If I understood everything I said I'd be a genius." ~ 'Unknown'

  12. #12
    Join Date
    Feb 2003
    Location
    North Kackalacky
    Posts
    3,473

    Default

    It's on my to do list when I get my Stevens 311 threaded for chokes.
    Vegetarian: Native American for Piss Poor Hunter

  13. #13
    Join Date
    Jun 2010
    Location
    charleston
    Posts
    8,600

    Default

    Quote Originally Posted by gooseaholic View Post
    It's on my to do list when I get my Stevens 311 threaded for chokes.
    You don't need choke tubes for that gun- just pull both triggers same time- I did it hundreds of times with 3" buckshot

  14. #14
    Join Date
    Aug 2017
    Posts
    35

    Default

    I turkey hunt with a 20ga SXS and had the same thing you have.
    my gun was regulated very good with 1oz lead field loads. with 1.25oz lead heavy pheasant loads out of turkey chokes started to see the right barrel pattern move right and left barrel patterns move left.

    POI to POA was worse with 1.5 oz of fed HVWT and even more so with TSS, the heavier the load of TSS the more exaggerated POI was off.

    I followed poor country preachers method of filing for the left barrel, he does say start with a tighter choke than you want to end up with as it will open up your pattern some.
    Filing did open the pattern up a bit but not by much, the pattern stayed round, some people said they got an oblong pattern after filing. I used a chain saw file, personally I wouldn't use a Dremel.

    Between the filing and dropping a 1 5/8s oz load of tss to 1 7/16ths it moved the pattern so POI matched POA

    for the right (close) barrel, I dropped the tss load down to 1oz of #9's and that brought POI back in line

  15. #15
    Join Date
    Dec 2013
    Location
    South Florida
    Posts
    2,423

    Default

    I suppose its possible with the TSS loads/wads you're getting some type of a "spin drift" effect which is moving your POI. Before I filed away at my choke tubes, I'd go ahead and contact William at Sumtoy and see if he has any chokes with a similar thread pattern that could be tested. Sumtoy chokes are designed to reduce the wad spinning out the end of the barrel and opening the pattern.... or possibly shifting it in this case.
    "Hunt today to kill tomorrow." - Ron Jolly

  16. #16
    Join Date
    Mar 2008
    Location
    Santee Swamp
    Posts
    16,874

    Default

    Shoot a lighter TSS load..

    Or just shoot a plastic gun at Turkeys like most errybody, and shoot flying fowl with the SxS
    Natural Born Killer Prostaff - Killing Tomorrow's Trophies Today...

    TFC -"Be tough or get tough"

    Conservation Permit Holder #5213

  17. #17
    Join Date
    Dec 2002
    Location
    upstate, sc
    Posts
    3,286

    Default

    Quote Originally Posted by crow View Post
    I turkey hunt with a 20ga SXS and had the same thing you have.
    my gun was regulated very good with 1oz lead field loads. with 1.25oz lead heavy pheasant loads out of turkey chokes started to see the right barrel pattern move right and left barrel patterns move left.

    POI to POA was worse with 1.5 oz of fed HVWT and even more so with TSS, the heavier the load of TSS the more exaggerated POI was off.

    I followed poor country preachers method of filing for the left barrel, he does say start with a tighter choke than you want to end up with as it will open up your pattern some.
    Filing did open the pattern up a bit but not by much, the pattern stayed round, some people said they got an oblong pattern after filing. I used a chain saw file, personally I wouldn't use a Dremel.

    Between the filing and dropping a 1 5/8s oz load of tss to 1 7/16ths it moved the pattern so POI matched POA

    for the right (close) barrel, I dropped the tss load down to 1oz of #9's and that brought POI back in line
    That’s a LOT of damn ciphering.
    \"We say grace and we say maam, if you ain\'t into that, we don\'t give a damn.\" HW Jr.

  18. #18
    Join Date
    Feb 2003
    Location
    North Kackalacky
    Posts
    3,473

    Default

    Quote Originally Posted by Bad Habit View Post
    You don't need choke tubes for that gun- just pull both triggers same time- I did it hundreds of times with 3" buckshot
    Vegetarian: Native American for Piss Poor Hunter

  19. #19
    Join Date
    Aug 2013
    Posts
    3,316

    Default

    Quote Originally Posted by Palmetto Bug View Post
    When choke tubes first became popular, I was working in a machine shop. We brought in our barrels and swaged, bored and threaded them to accept tubes that we made on a CNC lathe. We made the tubes with undersized bores, pattern tested them and bored them out to get good patterns. One of the most interesting things I learned in that process was that the changes weren't necessarily linear. You could pattern a tube, skin .005" out of it and it might throw a tighter pattern. Skin another .005" and it might open up considerably. It was like there was some separate metric that we didn't well understand, like maybe a harmonic, cyclic pattern. It could have just been voodoo or some other dark magic.

    I'm skeptical about the idea of predictably adjusting the POI, and simultaneously keeping the pattern, of a tube by asymmetrically grinding metal off, especially when you've already proven it is affected by different shot loads. But what do you have to lose? Crank up the Dremel. You might get lucky. Worst case is that you'll have to go buy another tube and find the right load.

    If you discuss this with a gunsmith or machinist, it's customary to talk about sizes in thousands of an inch. 1/100th of an inch is 10 thousandths and that's a lot when you're talking about choke diameters. A piece of typing paper is about 3 thousandths. Rolling papers are about one thousandth. (.001)
    I don't pay attention to any choke hype after seeing a thread on PredatorMasters forum years ago. No rhyme or reason what so ever to choke/shell/gun combinations and the guy had done a lot of testing.

  20. #20
    Join Date
    Oct 2003
    Location
    Charleston
    Posts
    18,402

    Default

    Quote Originally Posted by Kioti View Post
    I don't pay attention to any choke hype after seeing a thread on PredatorMasters forum years ago. No rhyme or reason what so ever to choke/shell/gun combinations and the guy had done a lot of testing.
    All reasonable people agree with you. But as you can see, instead of just using a different gun, this guy is going to file one side of a choke.

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •