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Shooter with poorly fit chokes wanted advice

Discussion in 'Uncategorized Threads' started by kirbythegunsmith, Feb 23, 2008.

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  1. kirbythegunsmith

    kirbythegunsmith Member

    Joined:
    Jan 3, 2008
    Messages:
    192
    Poorly fit chokes, now with lots of pictures to view

    I responded to a posting of a shooter that had a dangerous appearance to the choke fit of some new tubes. He may have been sold on the idea of getting tubes that matched the bore at the entry end of the tube. I can't imagine anyone thinking that it is OK to sell chokes made to fit closely in a choke hole in a factory barrel that they have never seen.

    Here is the posting location:

    http://www.shotgunworld.com/bbs/viewtopic.php?p=1095257#1095257

    The gun owner has posted some interesting picture that he took of the tube fit problem. It seems that he can see the edge of the tube from the breech end of the barrel! See his pictures for yourself, if you want to know what problem got me stirred.

    Here is my response:

    If you are really serious about finding what the problem actually is, you need somebody like me to physically examine the barrel and components.

    I have been like the lone voice in the wilderness for 23 years, telling shooters that choke holes (and sometimes tubes) can be crooked, and machining with non-concentric centerlines of the inside and outside is a possible fact.

    Since you are evidently seeing the edge from the breech position, you have what is known as a bore obstructive (or intrusive) lip exposure. The shot and fouling can pack under the edge and possibly lift the tube enough to cause a blow-out or bulge (and then blow-out). You do not need to make any other tests with a straw or any other amateur suggestions. You can see there is a problem already. You don't need any other noses to prove that you have something rotten.

    You should go see my website where I have articles and pictures posted that show crooked chokes, and be sure to catch the view of the exploding (almost) barrel in article 3. The choke tube is peeling inside out, the barrel is bulged and split, and another shell would have made it a grenade.

    Maybe after this, more shooters will think to pay attention when I say that there is a problem.

    If anyone is selling chokes (and have never seen that specific barrel) that are supposed to be an exact match for your existing bore size at the entry end of the tube, I call that FOOLHARDY. Too many factory choke holes are crooked to a substantial degree, and a blown out barrel is a bad price to pay for a pretend precision. I cannot emphasize enough just how much danger possibility exists and is multiplied by how many shooters in the same boat, but totally ignorant of the facts? It is possible to reduce the danger slightly (sometimes) by having a slanted edge to the tube entry, instead of a flat surface, but why have such an inconsequential gain from a supposed close fit when you have such a huge gain in definite danger possibilities?

    What happens to the goof that buys the tubes from another goof that decides to sell them later? Who is keeping track of what bore size was supposed to work with which particular tube? Now you may understand why I don't want to make precision chokes for any barrel that I didn't inspect (and preferably install a straight choke hole myself).

    Why do you think that factory made chokes are larger than the bore (at the entry end of the choke) in the first place?

    You are always more safe with a choke entry a little larger than the bore, than attempting to make a blind "precision" fit. Talk about a contradiction of terms.

    I really have a hard time believing that any choke manufacturer with even half of a brain would sell chokes that are supposed to be matched to a particular bore size at the tube entry without having any inspection at all. They should know better, or shouldn't be in business. Any shooter that buys into the notion of getting bore-matched chokes through the mail should have his head examined (once he understands the ramifications seen here).

    NEVER EVER shoot with a choke that has an exposed edge that you can see from the breech end. The future widow of the shooter standing next to you would be very grateful for the favor.
    I am not kidding.
     
  2. aa27zz

    aa27zz TS Member

    Joined:
    Jan 29, 1998
    Messages:
    45
    Okay, now I'm confused.

    Are you saying any time you wish to buy a replacement choke, you should send the barrel in for fitting?

    Are you saying that all manufacturers willing to sell extra and aftermaket tubes, without seeing the "specific" gun are "foolhardy"?
    Over the years, I've bought choke tubes from Giacomo, Kreighoff, Guerini, Beretta, Briley, Comp n Choke, Angleport, even Mossburg for my old camo turkey gun and NONE of them ever said 'send us your barrel'.

    I'll admit to being one of the "goofs" you mentioned. (My wife has called me a goofy ba$$$rd for years.) Heck, I'll even admit to being a lesbian!

    But, to call virtually all shotgunners "goofs" was hard to take without asking for clarification.

    Respectfully,

    Sam Hutchison
     
  3. ke4yyd

    ke4yyd Member

    Joined:
    Jul 15, 2006
    Messages:
    323
    Sam, I believe he was referring to custom made chokes designed to be the same measure as the barrel. Siminole Chokes are an example. They require the barrel to be sent in as every barrel is slightly different. However, if another choke is needed and they have your barrel size on record, then they will not need the barrel. Or you can send in one of their previous fitted chokes and they will match it. I personally do not know of any custom fitted choke makers that don't require the barrel for fitting.

    http://www.seminolegun.com/order.htm
     
  4. code5coupe

    code5coupe Member

    Joined:
    Jul 5, 2007
    Messages:
    955
    Kirby,
    I have to tell you: "centerlines" are not concentric.
    Holes are concentric.
    The definition of concentric is "having the SAME center". I.e. holes that are concentric share one center.

    (signed)
    The Nitpicker
     
  5. kirbythegunsmith

    kirbythegunsmith Member

    Joined:
    Jan 3, 2008
    Messages:
    192
    Poorly fit chokes, now with lots of pictures to view

    Dear pitnicker,

    I was explaining that the centerline of a barrel bore and choke hole in the end of that barrel bore might not align, and non-concentric meant not sharing the same center(line), and a choke tube can have the same situation i.e. where the inside hole is bored and the outside is turned without following the same center(line). Tubes in that condition might be referred to as being machined "eccentric" (not concentric).

    I do have this link to an online dictionary:

    http://dictionary.reference.com/browse/concentric

    http://dictionary.reference.com/browse/eccentric

    They all mention having a common center or center point and I figure center line falls in that zone.

    Anyway, we have a certain common ground of wanting clear explanations and pictures always help with that, so here are some nice examples of off-center chokes shown from the shot-catching end of the chokes.

    <a href="http://s186.photobucket.com/albums/x109/kirbythegunsmith/shotgun/?action=view&current=6.jpg" target="_blank">[​IMG]</a>

    <a href="http://s186.photobucket.com/albums/x109/kirbythegunsmith/shotgun/?action=view&current=4.jpg" target="_blank">[​IMG]</a>

    <a href="http://s186.photobucket.com/albums/x109/kirbythegunsmith/shotgun/?action=view&current=mis-aligned_choke_showing_edge.jpg" target="_blank">[​IMG]</a>

    Here is a set of pictures showing varying wall thickness of a choke tube skirt from a prominent manufacturer. Notice the small ding also present in the one picture, and that has been blued over, so it was present before packaging to sell.

    <a href="http://s186.photobucket.com/albums/x109/kirbythegunsmith/shotgun/?action=view&current=tg11.jpg" target="_blank">[​IMG]</a>

    <a href="http://s186.photobucket.com/albums/x109/kirbythegunsmith/shotgun/?action=view&current=tg10.jpg" target="_blank">[​IMG]</a>

    Normally I would show an off-center choke tube installation from the muzzle end, so here is a perfect (bad) example.

    <a href="http://s186.photobucket.com/albums/x109/kirbythegunsmith/?action=view&current=CH11.jpg" target="_blank">[​IMG]</a>

    This example is not so bad, and shows extra clearance allowance for safety. The preceding picture showed minimal safety clearance remained.

    <a href="http://s186.photobucket.com/albums/x109/kirbythegunsmith/?action=view&current=11a.jpg" target="_blank">[​IMG]</a>

    I had never expected anyone to think that buying aftermarket chokes was inherently dangerous, but I have seen enough to know that it cannot be claimed to be absolutely safe. Enough alignment problems exist to make perfect safety of any particular choke tube impossible to guarantee when no proficient inspection is performed with that specific combination.

    Here were a couple of examples that I posted long ago showing choke tube damage that could possibly cause a danger situation. If more postings happen here, I might post them in this thread, also.

    http://www.shotgunworld.com/bbs/cpg1410/displayimage.php?album=9&pos=48

    http://www.shotgunworld.com/bbs/cpg1410/displayimage.php?album=9&pos=49
     
  6. mercedesman1981

    mercedesman1981 TS Member

    Joined:
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    Messages:
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    Thank you for the explanations Kirby, I love learning new things.

    Mike
     
  7. AveragEd

    AveragEd Well-Known Member

    Joined:
    Jan 29, 1998
    Messages:
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    Location:
    Mechanicsburg, Pennsylvania
    I, too, thank Kirby for posting this thread. Our sport has a lot of amateur gunsmiths in it and I once thought chokes that exactly matched the bore diameter at their inlet were better. Then I bought a bore micrometer and could see by using it how little actual "jump" exists from bore to tube as well as how little actual distance is involved. Given the length of the shot column in the wad, it probably doesn't even know that gap exists.

    Ed
     
  8. JerryP

    JerryP Active Member

    Joined:
    Jan 29, 1998
    Messages:
    1,753
    I agree with Ed, how could anything really be gained by making the choke skirt dia. the same as the barrel dia. If such a choke were dropped it could easily be bent out of round. To make such a choke seems irresponsible to me.

    If resonable quality control is exercised there should be enough tolerance that an alignment problem should never happen will standard choke tubes or barrels.
     
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