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Why IM/F instead of F/XF ?

Discussion in 'Shooting Related Threads' started by Hammer1, Jan 26, 2011.

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  1. Hammer1

    Hammer1 Active Member

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    Why are the older fixed-choked trap guns choked for improved modified and full instead of full and extra-full ?

    I do have one Winchester Model 21 trap gun choked full and extra-full, but they're not common.

    .
     
  2. EuroJoe

    EuroJoe TS Supporters TS Supporters

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    old shells needed more choke than the new ones
     
  3. Hammer1

    Hammer1 Active Member

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    Wouldn't that mean that the older guns should be choked more, not less, causing full and extra-full to be more common than improved-modified and full among the older fixed-choked guns ?

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  4. jhoward

    jhoward Member

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    In many cases the definition of 'Full' and 'Extra Full' have changed. A lot of the older guns that are marked 'Full' will mic at .035" or even .040" of constriction where today .030" is pretty much standard for a 'Full'. So, even though they weren't marked as such, a lot of older guns are choked 'Extra Full' and 'Full'.
     
  5. ivanhoe

    ivanhoe Well-Known Member

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    More than likely the the model 21 that you have was ordered to shoot live birds as well as trap. Just a guess, it is after all shooters preference some preach IM some M I prefer F others prefer XF. Just a matter of what you like.

    Bob Lawless
     
  6. Hammer1

    Hammer1 Active Member

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    While my Winchester Model 21 is marked "Trap"...

    I was told it was ordered as a live pigeon gun.

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  7. short shucker

    short shucker TS Member

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    I've seen full being desribed as .030" and tighter. Some of the older guns I've seen as much as .043 as a factory full choke. The standard scale these days, for the 12ga, are as follows:

    .005 SK1

    .010 IC

    .015 LM

    .020 M

    .025 IM

    .030 LF

    .035 F

    I've seen XF maked as both .040 and .045

    ss
     
  8. EuroJoe

    EuroJoe TS Supporters TS Supporters

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    I thougt full choke meant" 70% of shot inside a 30" circle at 40 yards". The important thing is performance, not labels or markings.
     
  9. Unknown1

    Unknown1 Well-Known Member

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    Depends on what load you're shooting...

    According to Dr Jones' book, hard shot and fiber wads produce tighter patterns through the same choke than plastic wads and medium or soft shot. If the old shells contained hard shot they didn't need so much choke to throw a tight pattern.

    MK
     
  10. waverider

    waverider Well-Known Member

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    EuroJoe is right. But, that was the definition of a Full choke when hulls were paper and so was the wad. A .040 constriction would give you the percentage back then. Also back then IM needed .030 to get the percentage. That is now considered Lt Full.

    I think that the US should just adopt the .005 increment constriction table as the US or American standard of choke. Shooters need to shoot some patterns with their ammo of choice to find out what kind of pattern their gun and ammo shoots.

    Jason
     
  11. ivanhoe

    ivanhoe Well-Known Member

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    The man asked a question which doesn't have anything to do with a choke standard.

    "Why are the older fixed-choked trap guns choked for improved modified and full instead of full and extra-full ?"

    Now I have a Section of a document that was around long before the in between chokes were thought of



    [​IMG]



    So a choke standard just seems to be a little late to what I am seeing.


    Bob Lawless
     
  12. waverider

    waverider Well-Known Member

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    Bob,

    I am very sure that the table was developed with the standard .729 bore for 12 ga and shells that had paper wads and no shot cup.

    If you use the old constrictions with shells that have a plastic wad with a shot cup and no spreader post or insert you should see higher percentages.

    That is why I would prefer to see choke designations standardized with constrictions and the current .005 increment that Briley and a few others go by is fine with me.

    Jason
     
  13. ivanhoe

    ivanhoe Well-Known Member

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    Well Jason you are entitled to your opinion and I will not say you are wrong.

    I will ask this of you please tell me how what you are in favor of pertains to the original question of this post about older guns and how they are choked?

    Bob Lawless
     
  14. short shucker

    short shucker TS Member

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    Bob,

    I should have been clearer about why I posted the scale. A lot of older guns are choked tight by todays standards, but normal for the standards of the time of production.

    Depending on your POV todays guns could be considered lightly choked or in the same sense older guns could be considered over choked. It depends upon which set of standards you were raised on.

    I have a set of older fixed choke Beretta barrels thaty are marked IM/F. If you measure them out with a bore mic the bottom barrel is .029" and the top is .038". I would consider these barrels to be LF/XF to the set of standards I was brought up with.

    It's a potato/potato thing. They are all the same just expressed differently.

    ss
     
  15. ivanhoe

    ivanhoe Well-Known Member

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    short shucker if true bore(a barrel that is standard 12GA bore .729 full choke should be .035 or .694.

    So .038 can't really be X-full. The Barrels mentioned in the OP are true bore barrels. As I don't believe they were backboring barrels in the time frame of the model 21 trap.

    I understand that the numbers that are in the modern shotguns of today are anything but standard. The term Full choke is still .035 over bore It doesn't matter whether the .729 or 7.50 the constriction is still .035. This is one of the reasons that the shotguns of today are more popular as over bored barrels seem to be able to be custom tuned to the bores.

    I am just talking about the shotgun in the era or time frame that Hammer was referring to.

    Bob Lawless
     
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