Powder selection

Discussion in 'Reloading' started by wessman1, Jul 18, 2018.

  1. wessman1

    wessman1 Member

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    Just wanna pick your brains abit,what thoughts go into making your decision about powder selection for a particular caliber you may be loading for.I sometimes find myself scouring load books and online resources for a powder,and it may take me a week or two to come up with a powder to start with,especially on a new caliber I haven’t loaded before.I’ve been loading for 25 years and sometimes that’s the hardest decision to make.give me your thoughts thanks
     
  2. lancetkenyon

    lancetkenyon Well-Known Member

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    Generally, I look for what the majority of people are already using. Although a lot of cartridges are fairly similar, and what works for one usually is a good indicator of what will work in another similar cartridge.

    I also look to see what I will use the rifle for. All of mine are hunting rifles, and some pull double duty as long range steel bangers. So, for me, temp stability is vital. Meaning most of my rifles use one of the Hodgdon Extreme powders. Although, Alliant has come out with some powders that are far more stable than their old ones, like RL23 vs. RL22, RL26 vs. RL25, etc. and you can get better speeds with a lot of them.
     
  3. cape cove

    cape cove Well-Known Member

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    I will normally go to the bullet manafacture's loading manual of the bullet I chose and choose the powder that get's me the best velocity,if that is what you are after, and start with their lowest load and work up to the vel and accuracy I'm looking for.Most manuals will list several good powders for your chosen bullet. On line, as previously mentioned, is also a good place to see what other shooters are using.
     
  4. jimbires

    jimbires Well-Known Member

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  5. g0rd0

    g0rd0 Well-Known Member

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    me, I use a Prowley slide rule to find the burn rate powder for a new gun. Unfortunetly it is an OOOLLD version wich only lists IMR powders but, from all given powders on the scale I can then goto a burn rate chart to find a close if not identical burn rate powder
     
    Hand Skills likes this.
  6. Lonewolf74

    Lonewolf74 Well-Known Member

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    Not to hi-jack but I have a related side question.

    As others have stated I tend to search for what has been working well for others and reference a burn rate charge to see if slightly faster or slower may serve me better.

    For my question; can I SAFELY use starting charge weights from one powder to another that are close in burn rate?

    For example say I want to use IMR's new 8133 but can't find data for my application. However I have tested H1000 and know I can safely go to 79gr in my setup. Knowing this and that 8133 is slightly slower in burn rate can I start at 75-76gr of 8133 knowing I shouldn't hit pressure till 79 or more grains of powder?

    I guess really what I'm asking is will charge weights be similar if burn rate is similar?
     
  7. Kmccord

    Kmccord Well-Known Member

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    You can go to Hogdon website and find what they tested using IMR 8133 for a particular cartridge. I used it for my 28 Nosler but also found the load data was not far off from Retumbo.
     
  8. DUSTY NOGGIN

    DUSTY NOGGIN Well-Known Member

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    NO, nothing safe about guessing anything , call imr/hodgdon first ... vmd charts will show different volume per weight = capcities .... i couldnt find a volume for 8133 yet , IMO you should do some research before you proceed ... getting an email from the manufacturer would be ideal
     
    Last edited: Jul 19, 2018
  9. wessman1

    wessman1 Member

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    This is what I’m talking about where do the thoughts go when it comes to powder selection I can look at what others use but I want to know why.like what are the reasons why one might pick h1000 over retumbo for their 300 Winnie.When I started reloading 4895 was cheap and I pretty much used it exclusively even in my 25 Gibbs with lite bullets but I really didn’t know any better back then
     
  10. Lonewolf74

    Lonewolf74 Well-Known Member

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    Thanks for the replies and to help clear things up some.

    I have not done this because I am unsure of how capacity or volume vs weight in grains vs burn rate correlate.

    I have used starting weights based off another credible persons results with a given powder and bullet.
     
  11. Lonewolf74

    Lonewolf74 Well-Known Member

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    Wessman I'll lay out the process I went through with my 300wm and what brought me to the question i posted.

    Before I started any loading for my 300 I spent alot of time researching what others where having good success with. This brought me to 215 Berger hybrids and H1000 powder. In testing this setup I got good results but was a little slow in velocity. From there I tried RL26 based on ppl having good success and great velocity from it. I did find good accuracy and great velocity from 26 but it wasn't real consistent for me. One weather condition to another would show me a fair swing in velocity and ES would open up. Currently I'm testing N570 powder. There isn't any load data for this in a 300wm (hence my question) that I could find so I used the data from Broz' s testing to start with. I haven't nailed down a load yet but it shows promise and better velocity then H1000. With time I can test it more in different temps and weather conditions to see if it's stable and consistent. If it is it will be my powder of choice for this setup. If it doesn't work out I'll test IMR8133 next.

    For me it boils down to getting the best performance I can while still being stable and consistent. Stable and consistent trumps velocity so if I can't find consistency in any of the other powders I've tested I'll go back to H1000.
     
  12. Hand Skills

    Hand Skills Well-Known Member

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    When choosing powder, I was taught to cross reference between a couple of different loading manuals. Nosler and Speer are what I started with 20yrs ago.

    I like looking at 'case fill' or 'load density' also which can indicate if a powder is well matched to the application. Generally I'm looking for 95-100% case fill. Due to variance in powder lots (burn rate) and brass (case capacity), in practice these values can shift up and down, especially if seating depth is variable.

    Now with the internet it's possible to cross reference many more data sets. Just because two powders sit next to each other on the burn rate chart, does not mean they can be interchanged. The same way 2 bullets of the same weight cannot (always) be used interchangeably. I cross reference load data, and whenever possible use data from the manufacturer of the bullet I'm loading.

    For example here is some 300wm data from VV;

    IMG_8251.PNG

    N570 is not listed with the Berger 215. It is however listed with the lapua 220gr scenar.

    N560 is listed with both bullets, and the starting load is 3 grains less with the 215 Berger hybrid compared to the 220 scenar. Based on this information I would feel comfortable personally using a starting load of 74.8gr N570 with the Berger 215 hybrid (3gr less than the starting load for the 220gr scenar).

    This is an oversimplification of the math involved, and best practice would be to call both VV and Berger; ask their tech departments for their professional recommendation. I am not a ballistician, and as such cannot recommend anyone a load. Take my 'folk science' FWIW. I have been carefully and thoughtfully reloading for many years and have never had to pound a bolt open or pick brass out of my face.

    If I'm loading for stability, I typically prefer single based powders. These tend to have a lower bulk density and often are faster on the burn chart than a double based powder offering optimal velocity. The double based powders typically have both Higher bulk density and higher energy density. As result we can fit more 'grains' in a given case. More energy requires a slower burn rate (more time) to maintain a given peak pressure.

    Note: N165 is a single base powder. Though N165 data is listed for both 215 hybrid and 220 scenar, it is not suitable for cross referencing N570 which is a double base powder. I cross-referenced N560 because it is a double base powder, and much closer to N570 in chemistry.

    The keys to cross referencing;

    -Some bullets create more pressure than others due to bearing surface, jacket thickness etc. Be sure you are comparing the same bullet, not just the same weight of bullet.

    -understand energy density (kJ/kg); specifically Single base (nitrocellulose) vs double base (nitrocellulose + nitroglycerin) powders.

    -be conscious of bulk density (how many grains are useable in a given case, with a given bullet, at a given COAL). Run out of room, and you may need a faster powder. Run into pressure signs before the case is full and you may want a slower powder.

    Hopefully this post is of some value, and furthers the understanding of reloading dynamics. Reloading is not a mystical art, nor is it a hard science. My hope is that through sharing our processes, we move toward a better collective understanding of where science and art intersect.
     
  13. dougduey

    dougduey Well-Known Member

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    Like Hand Skills, I like to pick a powder that gives me 90-100% case fill and a listed velocity that I'm looking for. I've talked to the guys at Berger and Nosler a few times and they stated that's how they personally pick the powders they shoot with their rifles
     
  14. L.Sherm

    L.Sherm Well-Known Member

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    ^^^ this is what I base my decisions also on to get started on a load.