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groupings with black powder rifles

Discussion in 'Blackpowder' started by Flash!, Sep 29, 2008.

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  1. Flash!

    Flash! Member

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    I've had a black powder rifle made by Thompson for a few years and shot it with open sights. I have added a scope to it and today went to sight it in. I only managed 3 inch groups at 50 yards..... what kind of groups do you folks usually get with your black powder rifles?
     
  2. scrat

    scrat Member

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    Im thinking there is going to be to many variables. Powder type, weight, patch thickness lube. I think you maybe able to improve on your groupings but your going to have to change powder charge and record your results, then patch thickness, then lube types and powder type. You maybe able to improve. More range time for sure.
     
  3. Omnivore

    Omnivore Member

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    3" at 50 isn't terrible, but it's not really great either. If you're just starting out, you're not doing bad at all.

    How many different loads have you tried? Most any shooter will tell you that an individual gun will prefer a particular load over any other. How well can you shoot some other rifle? What groups were you getting before you mounted the scope?

    Adding a scope will do nothing to the inherant accuracy of the rifle, unless it's mounted poorly or it's defective, in which case it can only ruin accuracy.

    The U.S. military requirement for accuracy from the rack-grade M-14 (1950s) service rifle came to about about 6 inches at 100 yards. You're already there, using a more or less ancient technology.

    We're talking about a lot of different variables here, any one of which can influence accuaracy.

    bullet weight
    the consistency of the bullets
    rifling twist
    charge weight
    the consistency of your charge weight
    patch thickness (if applicable)
    the consistency of your patch thickness
    the amount of fouling present in the barrel
    the consistency with which you ram each load
    condition of the barrel
    condition of the all-important muzzle crown
    scope mounts
    scope rings
    scope condition
    your eyes
    the trigger action
    your skill level
    barrel to tang to stock fit
    lighting conditions

    I'm sure there are a lot of others.
     
  4. Omnivore

    Omnivore Member

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    You should tell us which Tompson Center rifle you're using. Someone on here can then recommend a srtarting load for it. Some of the really fast twist barrels, for example, don't do well with patched ball, by most accounts.
     
  5. Flash!

    Flash! Member

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    I am using the Thompson Black Diamond Express. I only tried one load. It is 2 50 grain pellets of Hodgon 50/50 pyrodex, 240 grain Thompson Center Mag Express Sabot, and Winchester 209 primers. I'm not sure if matters much with this load, but I was shooting in a 20 mph wind.

    With open sights I got about the same results and thought a scope would improve the groups. I am capable of MOA groups with my Browning A bolt, and today before I pulled out the muzzle loader, I was shooting one inch groups at 50 yards with a Yugo 8mm Mauser.

    After I got home, I gave this rifle a cleaning more thorough than it ever had and I'm headed back to the range later this week to try again. I'm thinking range time and different loads might be the key.... I'm still curious what size groups others are getting....
     
  6. scrat

    scrat Member

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    also remember to swab the barrel every few shots to remove fouling other wise you will never achieve any accuracy
     
  7. frontiergander

    frontiergander Member

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    you dont have to swab between shots to get excellent accuracy.

    It sounds like you need a thicker sabot.

    Try a 240gr xtp in a black mmp-12 or 24 sabot with 100gr pellets (or loose pyrodex rs-select)
     
  8. Cosmoline

    Cosmoline Member

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    As has been said there are many variables. Twist rate is critical. If you try to shoot PRB out of fast twist for conicals and sabots, you will not get good results. And visa versa. Fit is another factor. Oftentimes the barrels are rattle-loose in their mounts.
     
  9. Old Grump

    Old Grump Member

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    4 shot groups of 4" with 50 caliber patched balls and 90 gr of FFg Goex at 100 yards using an aperture sight. Same group as I get with my Mossberg and Winchester shotguns with slugs. Close enough for me. I'm never going to get 4 shots at a deer anyway. Anything out of that group can be contributed to shooter error. Shoots better when its colder. Because of that I no longer use slugs and I have never tried the sabots because of the cost.
     
  10. Pancho

    Pancho Member

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    Game shooters and target shooters are two different breeds. Game shooters know that they only have one chance to kill but the bullseye is much larger than the paper target. The game shooter is less critical because he has even more variables to consider. Distance to target is only one. Estimating distance is really tough in the real world of hunting.
     
  11. scrat

    scrat Member

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    oh shoot where have you been Pancho have seen you around in a while.
     
  12. Omnivore

    Omnivore Member

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    If you have the 28" twist barrel, that can stabilize full-bore lead projectiles (no sabot) of well over 400 grains. You have some experimentation to do.

    Using PRB from my 48" twist barrel with 110 gr Pyrodex RS I was getting 3 to 5" (three shot) groups at 100 yards, which is almost as well as I can shoot any rifle using iron sights.

    I then switched to real 2F BP, same charge volume, and I'm getting less velocity with larger groups and have to swab between shots or the tightly fit patched ball will stick on the way down. I could use a smaller ball with a thicker patch, fool around with the charge weight, or go to a conical and readjust the sights. I don't know, but it takes a lot of time to find that sweet load. Going back to RS and changing nothing else, I'd be OK with it.
     
  13. Cosmoline

    Cosmoline Member

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    Tinkering with the rifle can help too. I recently took the advice of bedding my smoke poles and using epoxy to fix the hook-breeches onto their mounts more solidly. The epoxy will wear out after a few trips, but it should give me better groups. On rifles that don't need a hooked breech there's some merit to just welding them together, though of course you have to know exactly what you're doing.
     
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