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choke quandry

Discussion in 'Uncategorized Threads' started by 99/100, May 12, 2007.

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  1. 99/100

    99/100 TS Member

    Joined:
    Jan 29, 1998
    Messages:
    5
    I have a Superposed trap that is choked mod. and full. The actual constrictions are .016 and .035 respectively. This seems normal except that w hen I patterened the barrels using my reloads of 1 oz. #8 at 1260 fps both barrels average 79% patterns at 40 yds. This is extra full. I would like to open up the lower barrel but I am very puzzled as to why both barrels would pattern the same. I have not tried other loads since this is my perferred load. Any thoughts as to why my barrels perform this way?
    Warren Hartz
     
  2. zzt

    zzt Well-Known Member

    Joined:
    Jan 29, 1998
    Messages:
    3,462
    Location:
    SE PA
    I'll also suggest you remeasure the Under barrel. It is more likely .026". There is no particular trick to getting 80% patterns at 40 yards with a B25 barrel choked IM or higher. If it really is .016", do as Andrew suggests. You can make a mint betting people on how it performs.
     
  3. IM390

    IM390 Member

    Joined:
    Jan 29, 1998
    Messages:
    213
    Actually your reloads will be better than store bought ammo because store bought velocities can vary greatly from lot to lot. I'll take a real good guess from my experience working with Don Zutz and say you will get a much different picture of your chokes if you would slow your loads down to 1200 fps or less. The two chokes look similar because you are beyond the separation point of full and modified. Compare patterns between the them by drawing a 30 inch circle of the pattern and then draw an interior circle of 20 inch on the same pattern, you would see the extra full showing a denser area in the interior center circle and a lesser pellet count between the two circles. A wider pattern by definition is one that is consistently better coverage (between the 20 inch line and the 30 inch line) so that a target cannot slip through that area. This is known as the annular ring. You don't mention what your load is. If you provide more information, maybe we can give you some direction without altering your load too much.
     
  4. 99/100

    99/100 TS Member

    Joined:
    Jan 29, 1998
    Messages:
    5
    I will attempt to answer all of your questions but one for now. I have averaged four patterns and they are fairly consistent. I actually counted the pellets in two shells in this batch (410). I have a permanent pattern board with pull down paper on a dedicated range with permanent measured markers and I take care to see that the muzzle is over the marker when I shoot. My GPS says that the range is 482 feet above sea level give or take a couple of feet. I have remeasured the bore and choke to verify the readings on the modified barrel. Using a telescoping gage and dial calipers the bore measures .725 and the choke at the muzzle measures .707. You do the math. The choke section is 3 7/16" long and is a straight taper. My load is 1 0z. of Lawrence Magnum shot, Clay Buster CB-1100-12, Winchester case, 20 gr. of Solo 1000 and a Cheddite 209 primer. It shows 1260 f.p.s. on the chronograph at 12' from the muzzle. I have not checked the difference between the annular ring and the center although I cannot see a difference in the density. I will do that next and post the results.

    For a comparison I shot three STS Light Handicap 3-1 1/8 7 1/2 and they were 72%, 66%, 66%. Still tight for a modified barrel. By the way I cut open one of these STS's and found the pellet count to be 423 with a weight of 507.2 grains. This is an illegal load by .2 grain according to the ATA rules.
     
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