weighting in on volume

Discussion in 'Shooting Accessories' started by JNG, Apr 24, 2008.

Help Support Muzzle Loading Forum by donating:

  1. Dec 6, 2013 #61

    Zonie

    Zonie

    Zonie

    Moderator Staff Member MLF Supporter

    Joined:
    Oct 4, 2003
    Messages:
    28,539
    Likes Received:
    1,208
    Location:
    Phoenix, AZ
    A number of years ago, Dixie Gunworks did an experiment with a .40 caliber barrel to see what shortening it would do to the muzzle velocity.

    They started with a 40 inch long barrel and fired a number of different powder loads using DuPont 3Fg powder under a patched roundball. They recorded the muzzle velocity for each length and load.

    With the lightest powder load of 38 grains they got the following:

    40" barrel = 1551 fps avg
    38" barrel = 1567 fps avg
    36" barrel = 1543 fps avg
    34" barrel = 1493 fps avg

    Note that with the shorter 38 inch barrel the velocity was a bit higher than it was with the 40 inch barrel.
    This tends to support that the barrel friction was slowing down the ball during that last 2 inches.

    The 36" and all shorter barrels lost velocity when compared with the 38 inch barrel.

    Going to the 47 grain and heavier powder charges, this slowing down because the powders gas pressure ran out of energy does not show up.

    40" barrel = 1770 fps
    38" barrel = 1747 fps
    36" barrel = 1735 fps
    34" barrel = 1610 fps
     
  2. Dec 7, 2013 #62

    hunts4deer

    hunts4deer

    hunts4deer

    40 Cal.

    Joined:
    Jul 22, 2010
    Messages:
    172
    Likes Received:
    6
    Location:
    Colony of Maryland
    Amazing! Zonie, Thanks for Posting.

    Makes me wonder how much powder is needed to not see any slowdown in a 56 inch 12 gauge barrel (Hudson Valley Fowling Piece)...
     
  3. Oct 30, 2017 #63

    csitas

    csitas

    csitas

    36 Cal.

    Joined:
    Oct 16, 2017
    Messages:
    61
    Likes Received:
    1
    I can't help my self here. I'm 74, and I guess come from the old school. I was always taught that you measure powder by volume. After you attain your volume , who cares how you duplicate it. It has always been preached, Do everything exactly the same .Soooo, If you must weigh, have at it till your content.Get there a pinch at a time THOUGH.
     
  4. Oct 30, 2017 #64

    hanshi

    hanshi

    hanshi

    Cannon

    Joined:
    May 7, 2009
    Messages:
    9,102
    Likes Received:
    303
    I'm a volume measurer, too. I might weigh the charge eventually just to see; but I still don't change anything.
     
  5. Aug 13, 2019 #65

    sonnyboy

    sonnyboy

    sonnyboy

    32 Cal.

    Joined:
    Jan 23, 2014
    Messages:
    14
    Likes Received:
    1
    Do they make an adjustable measure for 3f powder accuracy throwing, or is the world geared up for 2f powder measurement???. My adjustable measure has a smooth side which I can make a corrected (closer throw) measurement. The 50-60-70-80 calibrations are a waste to even try to throw accurate amounts.............sonny
     
  6. Aug 13, 2019 #66

    Kansas Jake

    Kansas Jake

    Kansas Jake

    54 Cal.

    Joined:
    Mar 23, 2015
    Messages:
    2,166
    Likes Received:
    203
    Sonnyboy, muzzleloader shooters almost always measure the black powder or appropriate substitute by volume and not by weight. So, 50 grains of 3f is the same volume as 50 grains of 2f etc. I have sometimes split the 50-60 etc grain calibrations to make 5 grain adjustments. One could also eye ball to smaller differences. For me, most of the time 5 grain intervals works fine in working up a load in larger (50+ caliber) guns. I may make smaller adjustments for small caliber stuff.
     
  7. Aug 13, 2019 #67

    Grenadier1758

    Grenadier1758

    Grenadier1758

    58 Cal.

    Joined:
    Oct 9, 2004
    Messages:
    3,379
    Likes Received:
    458
    Location:
    St. Louis, MO
    The tiny difference in volume between 50 grains of 3fg to 2fg isn't going to make any difference in performance. Black powder is not that sensitive to the small variations in weight from one measurement to the next.

    You do want to use the same measure for your volume measurements as there can be quite a difference between measures. I have seen up to 5 to 10% difference.

    The synthetic black powder substitutes are designed to perform to similar volumes of real black powder.
     
  8. Aug 13, 2019 #68

    SDSmlf

    SDSmlf

    SDSmlf

    40 Cal.

    Joined:
    Nov 4, 2006
    Messages:
    829
    Likes Received:
    281
    Location:
    Western North Carolina
    When measuring BP charges consistency will be your friend. Different volumetric powder measures will result in slightly different charges. Find a measure you like and stick with it as you develop your best load. Use it the same way every time - for example, do you tap it to settle the powder?; do you level off the charge by eye or pass a knife edge over it (possibly your measure has a funnel type attachment that levels)?; etc. The actual exact charge weight isn’t as important as it being reasonably consistent from shot to shot. Plus these measures are not calibrated nor held to NIST standards.
     
    45man likes this.
  9. Aug 14, 2019 #69

    Alice1885

    Alice1885

    Alice1885

    32 Cal

    Joined:
    Nov 1, 2017
    Messages:
    14
    Likes Received:
    3
    Location:
    Eastern Ohio
    If you want a consistent powder measure, that measures by volume find you an old Belding & Mull powder measure. They are the most consistent out there. Heck the Schutzen guys use them so if they are good enough for them, they are plenty good naf fur us. You won't be disappointed I gurantee it.
    Alice 1885
     
  10. Aug 14, 2019 #70

    Grenadier1758

    Grenadier1758

    Grenadier1758

    58 Cal.

    Joined:
    Oct 9, 2004
    Messages:
    3,379
    Likes Received:
    458
    Location:
    St. Louis, MO
    If your most accurate load is 65 grains of 3fg (volume) in your measure, what real difference does it make if that volume of 3fg weighs 63.5 grains or 66 grains on a weight scale? Or that that volume of 2fg will weigh 63 grains? If that volume gives the best performance for target or hunting, use that volume measure always.

    Now I can see an instance where you have a super performing load of 65 grains volume that weighs 64.7 grains on your weight scale and you want to pre measure 25 loads for an important match, then use the weight scale to sole out those loads.

    A few years ago I ran measurements of 10 volume measures. Most were fairly close to the 2fg weight. 3fg weighed a grain or 2 more at 100 grains setting. The deviation from one measurement to another was about a grain if I was careful and consistent in using the volume measure.

    The conclusion I reached was to pick one measure and use that one.
     
    Last edited: Aug 14, 2019

Share This Page

arrow_white