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Thread: Powder lot change / velocity change IMR 4064

  1. #1
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    Powder lot change / velocity change IMR 4064

    Pappabear and I Shot some 178 ELDs out of his 16 inch LMT MWS today. I spun up 50 rounds of ammo in MEN brass with 2 different lots of 4064. Ammo was loaded on the Chargemaster on the same day, same everything... except for the powder lots.

    We had the last half pound of an 8 lb jug that had a Vicks Vapor rub smell to it.... I mean STRONG. I'd loaded a bunch of 4064 before, but this 8 smelled odd. In any case.. the Vicks powder shot 98 fps FASTER than the newer lot of 4064.

    We had seen a 60+/- change in velocity with Varget before... and I did a thread on that, but this was crazy. Almost 100 fps difference.

    The hot stuff has a 2015 production code, and the milder powder is 2016 date coded.
    "What would a $2,000 Geissele Super Duty do that a $500 PSA door buster on Black Friday couldn't do?" - Stopsign32v

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    I cannot offer knowledge, only opinion and observations of similar phenomenon. If one were to charge the cases by volume instead of weight I suspect the velocities might have been much closer. Did they bulk the same?

    From what you have said the lots were not really that old compared to what many of us might find in our closets. I therefore assume you are referring to lot to lot variation only in your query.

    Whether it is a drying or evaporation of a component of manufacture or a deterioration of the "active ingredients" it is just maddening... I guess one question that should be asked is; did your load with the original lot produce velocities that were in line with prior results, or had the powder become supercharged?
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    I have 16lbs of 4895 that is so fast I cannot use it in a 6BRA (4895 being the go to powder for this cartridge). It was the newest (at the time) lot of 4895 available, and I had to wait it out until a newer lot came out that would actually work with the 6BRA.

    I also have some (as in almost out) powder that was pulled from tracer rounds left over from Vietnam. This is the powder that dominated Short Range Benchrest competition to the point that 8208XBR was developed as a clone to it. To this day it still has the same burn rate, for everyone that still has any left (you see it getting shot at Nationals and other big events).

    Both age and enviromental conditions can/do affect powder, as we all know. Sometimes I wonder if these wacky lots of powder come that way from the manufacturer or if something occured during shipping or at the vendor which cause the powder in question to behave so differently from what we expect.
    Last edited by masan; 05-07-18 at 07:22.

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    I don't suspect any temperature abuse or mis-handling. Just an impressive velocity swing. The older (menthal) powder actually popped a primer. That load was too hot. 42.3 gr yielded 2560+/- fps with a 178 out of a 16 inch gas gun. That's almost 20" bolt gun speed.
    "What would a $2,000 Geissele Super Duty do that a $500 PSA door buster on Black Friday couldn't do?" - Stopsign32v

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    I think it would be quite interesting to see what the charge weights would differ if you have a measure that throws a relatively precise volume. Then with a charge weight of the hot lot you are comfortable with to see what matching volumes would do.
    Patriotism is supporting your country all the time, and your government when it deserves it. Mark Twain
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    Quote Originally Posted by 308sako View Post
    I think it would be quite interesting to see what the charge weights would differ if you have a measure that throws a relatively precise volume. Then with a charge weight of the hot lot you are comfortable with to see what matching volumes would do.
    If markm is also interested in this, I am willing to put my Culver styled measure from Bruno's up for the experiment. I don't use it to load for BR Competition anymore so I won't be in a bind without it for a few weeks.

    It will accurately measure to 0.1gr by volume, so long as the user is consistent.

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    I have a Harrels powder measure at the house. Pappabear had bought it for throwing 4064.... but I never got consistent with that powder in the unit. I need to revisit that equipment.
    "What would a $2,000 Geissele Super Duty do that a $500 PSA door buster on Black Friday couldn't do?" - Stopsign32v

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    Smokeless (nitrocellulose and nitrocellulose-nitroglycerin) propellant starts to deteriorate from the moment it's manufactured. Manufacturers normally add an anti-oxidant preservative (up to 2% diphenylamine) to reduce the effects.

    How the powder is stored can affect how fast it breaks down. I don't have the experience to say whether blending the two lots is a good thing as once the stuff starts to go there's an age curve. Some powder is usable for 50 years or more, some starts to fail quicker.

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    Is there a difference between ball and extruded? I've read that ball is less prone to deterioration.
    "What would a $2,000 Geissele Super Duty do that a $500 PSA door buster on Black Friday couldn't do?" - Stopsign32v

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    The chemical composition is typically the same, it's how it's formed. The whole process is usually underwater.

    Ball powder is formed from dies kind of like shower heads -- as the propellant is forced from the fixture it forms into round drops and sinks.

    Stick propellant is extruded from a fixture like out of a sausage grinder. Extruded propellant cools into pencil lead-like sticks and each is cut to selected lengths as it comes out of the fixture.

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