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.742 chokes in .740 barrels - bad idea?

Discussion in 'Shooting Related Threads' started by Kevin Fleming, Apr 23, 2012.

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  1. Kevin Fleming

    Kevin Fleming Member

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    I am using inv+ chokes in a .740 bore gun. I purchased an invector + tube from another TS.com'er which is marked ".742". My other tubes are marked "740". Upon using it I noticed that the wads were losing a lot of petals, so I replaced it for fear the wad was catching on the end of the tube. The fact that the "742" is larger diameter than the "740" tells me it should be a larger diameter than the barrel, and in fact it mics at 0.755" opening, about 5 thous larger than the .740. It is worrysome tho how the wad petals were stripping off on about half the shots fired. As background, these wads are prone to loose a petal now and then, but with the 742 tube, often 1 or 2 petals were coming off, and occasionally 3. What does this mean - I cannot find anything to explain petal loss. The 742 tube is in very good condition and appears to be perfectly round, with the soot buildup very even and symetrical. Should I use this tube?

    K
  2. Ahab

    Ahab Active Member

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    Sure ... go right on using it IF you don't mind having the gun spit it out and ruining the barrel!
  3. dudleyone

    dudleyone TS Member

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    Kevin, I would change wads also. If the barrel was smaller than the choke tube it would be a different answer. If you measure the choke tube, you should find that the "lead in" (choke tube measurement where it meets the barrel), will be several thousandths larger than the bore, for safety purposes.Also, each barrel may be a little different than the others.As an example, I just measured the barrels of a Kolar I recently bought. The unsingle barrel measured a .742 bore, while the O/U barrels were each .740.No big deal.Enjoy your purchase.
  4. Rebel Sympathy

    Rebel Sympathy Member

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    .742" chokes in .740" barrel. Hmmmmm! What do your survival instincts tell you???

    Mike
  5. Bob Hawkes

    Bob Hawkes TS Member

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    That's what they make bore guages for, be sure, not sorry.
  6. letts

    letts TS Member

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    If I did this correctly, check out this write up from TrapshootingUSA Herb addresses this very issue

    http://mag.digitalpc.co.uk/fvx/bbp/tsusa/1003-04/





    Letts
  7. BAD 303

    BAD 303 Active Member

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    The wads being stripped by the type of choke not the fact it is .002 bigger than factory chokes. You could have .002 build up in plastic in a choke and never in this lifetime know any difference. Use it and forget about it. .002 means nothing in a choke tube. The mouth is where the problem would arise and it will be bigger not smaller. Screw it in and don't sweat it.
  8. Kevin Fleming

    Kevin Fleming Member

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    The magazine article was informative, and said what I already thought - that a larger choke bore couldn't be detrimental. In fact, Wright states that the skirt diameter should be 12 thous larger, or more, than the (stated) bore due to barrel making tolerances (thanks Letts).

    Still a mystery about the stripped petals. This only manifests itself with one wad I use. I don't care to change because it patterns very well for me. Probably just a characteristic of the wad design.

    K
  9. Hill topper

    Hill topper Member

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    Kevin,

    Seems to me loading a few wads of a different type would be in order to see if the problem continues.

    ed
  10. scooterbum

    scooterbum Active Member

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    Are these wads European?
  11. Kevin Fleming

    Kevin Fleming Member

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    I sent pms to particular questions. I do not want to post up anything that might be taken as disparaging as I am losing petals with 2 different tubes each from different manufacturers. Also as I said, this wad seems to lose petals pretty consistently, but all wads have a petal break off now and then, and these perfrom VERY well. The common denominator may be construction. I do not notice the issue using .020 choke, but then that is on 1st shot of doubles and I try not to watch the target after the shot is released.

    I'm probably overconcerned about a unimportant detail.
  12. scooterbum

    scooterbum Active Member

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    Not enough info. Should have said that from the beginning. You are not forthcoming with the information. Do you think we are mindreaders?
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