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Thread: Powder Charge Weight or Velocity - When to stop?

  1. #1
    Boolit Man
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    Question Powder Charge Weight or Velocity - When to stop?

    Powder Charge Weight or Velocity - When to stop?

    I was loading 45 Colt in Starline brass with a 260 grain soft cast BHN ~10 lead bullet and Hodgdon's CFE-Pistol powder.

    My chrono testing showed the velocity I was getting from my 5.5" barrel Ruger New Vaquero was 30 fps faster then the maximum velocity listed in the Hodgdon Annual Manual magazine and I was still 2 tenths below the maximum recommended powder charge weight for standard (low) pressure 45 Colt loads.

    Should I trust the chrono results and back off my powder charge weight slightly to bring down the MV (and pressure) to the velocity Hodgdon got while testing at their max powder charge?

    Or continue adding powder to book max and and be over joyed at the velocity increase I will be getting and trust Hodgdon that I'm not exceeding pressure limits using their load recipe?

    If I didn't have a chrono I would know what was going on and the above questions would never enter my mind. Ignorance is bliss till something goes KBOOM then your scratching your head if its still on your shoulders.

    I also want to use my load in a new Winchester 1873 rifle I have on order, so the increased MV would be a big boon for rifle usage, but not if the increased MV is exceeding the standard pressure limits for the 45 Colt cartridge. Looking for advice from more experienced reloaders on how should I proceed.

  2. #2
    Boolit Master Nobade's Avatar
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    Does that 30 fps really matter? Load for accuracy, velocity doesn't mean much if you don't hit the target.

  3. #3
    Boolit Master
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    "Powder Charge Weight or Velocity - When to stop?"

    Posts like this have no real answer. There will be many answers. Chose which you want.
    What will you do when you change lots of powder? What will you do when you change lots of primers?
    Two tenths grain of powder when the powder, on the average, will be farther apart just by changing lot numbers?
    Really, just think about it. Ive chronoed 50 fps differece in changing lots of primers.
    Just think on all this and you will see two tenths grain of powder is really nothing
    We Know Mass Cannot Be Weighed But It Has Newtonian Weight And That Is Derived From Kilograms And Kilograms Can Be Converted to Pounds. But, Still Mass Cannot Be Weighed. But How is the kilograms obtained? Can Kilograms Be Weighed? Evidentally Yes It Can. But, Still Mass Cannot Be Weighed So Kilograms Must Not Exist. Funny Isn't It.
    One good thing out of this the next time I'm at the doctors and they want to weigh me I'll tell them mass cannot be weighed.

  4. #4
    Boolit Master
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    greenjoytj - your question is based on a lot of variables so the answer isn't going to be set in stone.

    Starting with the velocity, unless you're comparing apples to apples, that's not a good measure of pressure. Different barrel lengths, cylinder gaps, lead alloys and a bunch of other things, will effect muzzle velocity.

    Bullet type - looking at Hodgdon's on-line data for 45 Colt loads for 260 grain bullets and CFE Pistol powder, I only see data for a JHP [jacketed hollow point]. And, that data is from a 7.25" barrel. I don't know if that's the same data you are looking at but if it is; that's not the same combination you're shooting. A lead bullet generally requires less pressure to achieve the same velocity as a jacketed bullet with all other factors equal.

    Strength of the Vaquero - the Ruger Vaquero is a strong gun, so 30 fps over listed velocity at .2 grains below max charge weight; wouldn't even make me blink.

    Bullet style - The seating depth of similar weight bullets can vary based on the style of bullet and location of the crimp groove (assuming you are crimping at the crimp groove). So your bullet may not result in the same case volume when seating to the same OAL as seen in the data. That change in case volume will effect pressure and therefore velocity.

    And as others have said - 30 fps isn't a huge difference.

    If you are loading within the parameters of the listed data (OAL, bullet type & weight, powder type & weight, etc.) I wouldn't focus too much on what the chronograph reads.

  5. #5
    Boolit Master


    Larry Gibson's Avatar
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    greenjoytj

    Since you can't measure pressure unless you are using the exact same components and barrel length as Hodgdon there is not a precise enough comparison there based on velocities. The 30 fps faster velocity measured (you don't give the # of shots) may well be closer to or less than the published velocity with the next test (should be 10 shots to approximate the Hodgdon data).

    Given the strength of your Ruger and that Hodgdon's data is under or at SAAMI MAP level unless you are getting obvious signs of pressure beginning with harder than normal extraction then look at accuracy as mentioned.

    Neither the 30 fps or the .2 gr difference mean much of anything without further testing.
    Larry Gibson

    “Deficient observation is merely a form of ignorance and responsible for the many morbid notions and foolish ideas prevailing.”
    ― Nikola Tesla

  6. #6
    Boolit Master OS OK's Avatar
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    I watch the radius on the edge of the spent primers. Here I have the 900 FPS I wanted with a PC'd 200g. SWC...these primers look fine to me. I'm more concerned with the groupings and will accept whatever speed I get when the groups are tight.



    Here, with this 9mm I've gone too far...the primer is starting to flow, to copy the machine marks on the breech face, they will even try to flow into the firing pin hole around the firing pin...the edge of the primer is now a sharp corner and the radius is gone...if you increase the charge from here the primer will completely fill the radius edges of the primer pocket and you are going to have a primer rupture sooner than later.



    To avoid having to distinguish between different primer manufacturers cup thickness and try to cipher how they all react to high pressure I try to use only CCI primers...or only whatever you have available so long as you are used to scrutinizing those cups.
    This is a rough estimate of pressure but it generally runs the same in rifle pistol and is a good way to stay out of self created problems, without sophisticated pressure testing equipment, I don't have any other way to stay on the safe side.
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    just, "watch your 6" .

  7. #7
    Boolit Master
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    Now you see what I was saying. Each person will have an answer. After you get 20 or 30 answers cut little,pieces of paper, write the number of each post suggesting what to do on each little individual piece of paper and put them in a hat. Shake them around, close your eyes and draw one out.
    WaaLaa the answer.
    Just a little jocularity here but this what it amounts to.
    Let us know which you pick.
    We Know Mass Cannot Be Weighed But It Has Newtonian Weight And That Is Derived From Kilograms And Kilograms Can Be Converted to Pounds. But, Still Mass Cannot Be Weighed. But How is the kilograms obtained? Can Kilograms Be Weighed? Evidentally Yes It Can. But, Still Mass Cannot Be Weighed So Kilograms Must Not Exist. Funny Isn't It.
    One good thing out of this the next time I'm at the doctors and they want to weigh me I'll tell them mass cannot be weighed.

  8. #8
    Boolit Man
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    Two 10 Shot groups were fired across the chronograph.
    Also reviewing my notes on this load I see the difference in my load vs the Hodgdon recipe that I’m using as the benchmark. My cast bullets are 10 grains heavier and I substituted CCI 350 Magnum primers as that’s what I had on hand for Winchester LP. I suppose my primer maybe more energetic that the WLP version. Winchester does say their primer is suitable for magnum loads. I use the CCI 350’s when I load black powder in the 45 Colt which is my usual propellant.
    The smokeless load I reported using was my first foray into smokeless powder in the 45 Colt.
    I chose to use CFE-Pistol based on the high MV reported by Hodgdon in their manual, but was shocked at the MV I got. My BP loads (35grs 2fg GOEX) get me 823 fps so seeing +200 fps MV got me thinking that maybe I’ve exceeded the 14k psi pressure standard by a large amount.

  9. #9
    Boolit Master gnostic's Avatar
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    Quote Originally Posted by OS OK View Post
    I watch the radius on the edge of the spent primers. Here I have the 900 FPS I wanted with a PC'd 200g. SWC...these primers look fine to me. I'm more concerned with the groupings and will accept whatever speed I get when the groups are tight.



    Here, with this 9mm I've gone too far...the primer is starting to flow, to copy the machine marks on the breech face, they will even try to flow into the firing pin hole around the firing pin...the edge of the primer is now a sharp corner and the radius is gone...if you increase the charge from here the primer will completely fill the radius edges of the primer pocket and you are going to have a primer rupture sooner than later.



    To avoid having to distinguish between different primer manufacturers cup thickness and try to cipher how they all react to high pressure I try to use only CCI primers...or only whatever you have available so long as you are used to scrutinizing those cups.
    This is a rough estimate of pressure but it generally runs the same in rifle pistol and is a good way to stay out of self created problems, without sophisticated pressure testing equipment, I don't have any other way to stay on the safe side.
    OS OK nailed it. Notice the firing pin is dragging as well. The case is starting to eject before the firing pin retracts. I've used this method for 50 or 60 years and it's served me well...

  10. #10
    Boolit Man
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    I see the horizontal scratches across the face of the primer. The edge of the primer dimple at the 7 o’clock position shows it flatened or altered in that small area as it not the same sharp dimple edge profile as other parts of the dimple.
    I’m going to add a hand held magnifying glass to my reloading kit so I can get a better read on primer condition.

    Thanks to everyone that replied, I value all the advice given.

  11. #11
    Boolit Master
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    I'm just looking for accuracy .

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Abbreviations used in Reloading

BP Bronze Point IMR Improved Military Rifle PTD Pointed
BR Bench Rest M Magnum RN Round Nose
BT Boat Tail PL Power-Lokt SP Soft Point
C Compressed Charge PR Primer SPCL Soft Point "Core-Lokt"
HP Hollow Point PSPCL Pointed Soft Point "Core Lokt" C.O.L. Cartridge Overall Length
PSP Pointed Soft Point Spz Spitzer Point SBT Spitzer Boat Tail
LRN Lead Round Nose LWC Lead Wad Cutter LSWC Lead Semi Wad Cutter
GC Gas Check