3/5 Bismuth patterns

Discussion in 'Shooting - Reloading Forum' started by JohnBZ, Sep 2, 2019.

  1. JohnBZ

    JohnBZ Elite Refuge Member

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    I got a small window today to pattern some boss 2.75" 1.25oz 3/5 @1350 fps bismuth. I used a browning BPS with a 26" barrel (invector plus). Temperature was 80 degrees. Overall the results were disappointing. I tested a carlson extended modified, a factory full choke and an older ext patternmaster. Back to the drawing board.


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  2. 10GAGENUT

    10GAGENUT Elite Refuge Member Sponsor

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    I'm not knocking but those are pitiful to say the least for forty yards, sorry I know you paid for them just being honest.
     
    Last edited: Sep 2, 2019
  3. derbyacresbob

    derbyacresbob Refuge Member

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    It would be interesting to see how just a straight load of bismuth #5 shot would pattern at 40 yards. According to KPY's bismuth pellet counts 1-1/4 oz of Bismuth #5 shot would have about 45 more pellets than the 50% X 50% #3 and #5 duplex load would have.

    I am surprised that you didn't get a bigger difference in patterns between the Mod and the Full chokes.

    The #5 bismuth at 1350 fps gets 1.55" of gel penetration at 40 yards so the bismuth #5 shot should do a good job on ducks.

    For geese the bismuth #3 shot at 1350 fps gets 2.13" of gel penetration at 40 yards.
    For geese the bismuth #2 shot at 1350 fps gets 2.42" of gel penetration at 40 yards.

    All three shot sizes started out at 1350 fps, Pellet speed at 40 yards and time to 40 yards.
    #5 bismuth 678 fps at 40 yards and time to 40 yards was .133 seconds
    #3 bismuth 735 fps at 40 yards and time to 40 yards was .127 seconds
    #2 bismuth 757 fps at 40 yards and time to 40 yards was .125 seconds

    The #3 and #5 duplex load would have to have a longer shot string than a load with one shot size because the pellets don't arrive at close to the same time like a load with one size of pellets.

    I think I would rather just shoot straight bismuth #4 shot or bismuth #5 shot for ducks and use bismuth #2 shot for geese.
     
  4. JohnBZ

    JohnBZ Elite Refuge Member

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    Id agree. Especially when Im used to steel giving me 80 - 90% patterns at 40 yards. Im going to try some different chokes and see if I can get this load controlled.
     
  5. Tuleman

    Tuleman Elite Refuge Member

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    Be interesting to see what the patterns looked like at 35 yards.
    I wouldn't be shooting that combo at 40 yard ducks, but it might be an entirely satisfactory combination at even slightly-shorter ranges.
    (Of course, if it were, what would be the point of bismuth, since steel is a perfectly-good <35 yard load......?)
     
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  6. 10GAGENUT

    10GAGENUT Elite Refuge Member Sponsor

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    I beleive that Bismuth can do much better than that if you look at the 10 gauge pattern pictures above I can duplicate that kind of performance with 12 ,16 and 20 gauge loads. I may make up some 12 gauge loads and shoot some patterns with them just for comparison. What it all boils down to IMO is using quality components and temperature stable powders, as all of those 10 gauge loads were fired in temperatures not much different than you shot yours.
    See what I can come up with.
     
    Last edited: Sep 3, 2019
  7. Sunklands

    Sunklands Elite Refuge Member

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    I’m betting most folks who are buying the biz, are buying it to increase their range, to “lead like” performance, not the benefits of it in older barrels. As Joe, pointed out, those are lackluster patterns for a 40 yard load. Typically factory full invector chokes, are pretty dang good, so I’m surprised to see that pattern so loose.
     
  8. Sunklands

    Sunklands Elite Refuge Member

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    Was bout to buy some Boss biz myself, glad you told me, that I prolly wouldn’t be to impressed.
     
  9. JohnBZ

    JohnBZ Elite Refuge Member

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    I share the bad as well as the good. The manufacturer told me to put the shells in my refrigerator for a couple hours and see if the patterns improve. They seem to think the velocity is too high at 80 degrees so the patterns are blowing up. Per the supplied sheet they are running 1427fps at 71 degrees. They contend to control bismuth at those velocities you have to choke it tighter. He also recommended having the forcing cone lengthened. I wont likely do any forcing cone work considering the barrel is back bored. I think my first step is going to be a tighter choke or maybe an extended full. I will likely retest in cooler weather as well. Im not about to give up yet. Sometimes it takes a little work up to get a good pattern.
     
  10. 10GAGENUT

    10GAGENUT Elite Refuge Member Sponsor

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    Give it a try maybe it will work for you.
     

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