View Full Version : 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.
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?
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.
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.
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.
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.
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.
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.
Is there a difference between ball and extruded? I've read that ball is less prone to deterioration.
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.
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.
Harrels are as good as anything out there, better really. Culver style measures, like the Harrels, perform best when operated in a certain manner. Feel free to PM me if interested, it isnt something that I can explain by typing, usually need to physically demonstrate.
Like I said, pm if interested.
Mark has loaded ammo cans of full 168 SMK for us to shoot out of the LMT MWS, so I grabbed that thrower. He never warmed up to it as he is stubborn in his proven ways. I said for thumping steal ammo we can deal with less than .5 Moa, maybe this will tempt him. Thanks for the offer. He just loaded 200 rounds of 300WM that is .25 to .5 MOA stuff that we are going to do a 300 test with 3 , 300's this Sunday and do write up.
Im expecting some pretty impressive results.
PB
I gave up on my thrower when I stopped loading my ammunition at the match. They are the best when you are trying to make ammo between matches and cycle brass properly. Loading from home and not worrying about cycling brass is just better, at least for me. I am interested to hear what results you guys come up with.
The appeal of the thrower is speed. I've not given up on the thrower. It's just a matter of finding time to work on new projects. Sunday was a 12 hour, non stop win mag loadathon.
They are about the fastest way to get powder into the case. With a little practice and some Sharpie marks, they can also be pretty accurate.
They are about the fastest way to get powder into the case. With a little practice and some Sharpie marks, they can also be pretty accurate.
Can you expand on pretty accurate? How much variation is there in throws? .5 .2 1.0?
PB
Can you expand on pretty accurate? How much variation is there in throws? .5 .2 1.0?
PB
With my measure I can get .1 pretty regularly, though it will occasionally drop up to .3
Here is a link to a recent discussion I am part of about measures and scales and how accurate our measures really are (mine is the second post, where I describe the method I used to try and determine my measures accuracy):
http://forum.accurateshooter.com/threads/more-practice-with-the-measure-and-success.3951725/
edit:
The I.D. of the drop tube you are using plays some role, more in how well the powder will pack but also in the accuracy of the measure.
Interesting. Do you think 4064 is realistically possible to achieve .3 gr variance? That stuff is like rice. I could run shorter kernels in it (like Varget) too. Bulk loading (100 rounds or more) on the chargemaster gets exhausting.
I feel you on the ChargeMaster, I typically load up 200-400 rounds for competitions, rough weighed on the ChargeMaster then checked/trickled on the FX 120i, it can get tedious.
The way the Harrels measure is designed it should be fine with the 4064, though you are pretty much guaranteed to end up cutting some kernels of powder.
I would check to make sure the ID on your drop tube is 1/4" and not 3/16".
If you want to PM your email address I can make a cell phone video of the "tricks" to eek out some more accuracy from the measure.
Mark, I'd take masan up on the Harrel's loan. I get around the drudge by using two Chargemasters.
Mark, I'd take masan up on the Harrel's loan. I get around the drudge by using two Chargemasters.
I have a Harrel's already... just haven't rotated it into production. Two chargemasters would be sweet if I could leave them in place. I don't have the space to leave them out however.
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