IMR 4064 compression

[Dre_sa]

Greetings all,

I recently got a bunch of 152 gr controlled chaos bullets and am loading them into .308 winchester.

Looking at my lyman manual the load data suggests a powder charge range of about 42 to 47 grains.

I loaded a few at 43.5 gr of the 4064, thinking it should be a decent middle ground. It did however compress the charge a bit, and having loaded for 175gr previously, I've not noticed that before.

So the question is, how does 4064 react to compression? I'm seeing a lot of max loads in the manual are compressed. Is it a non issue for this powder?

How does one even fit 48gr of 4064 in a .308 case? (Max for 150gr bullets)

Thanks for sagely advice in advance

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[Metal god]

The answers are it handles being compressed just fine . How do you get long stick powder to fit in a case ? Drop tube or vibration to settle the powder . I must use a drop tube when loading IMR 4064 and 77gr smk in 223 cases . Big time crunch if I don’t.

Just keep in mind over compressing can bulge the case . Or if you are using a seating die that uses a spring on the ceiling stem you can get inconsistent seating depths . You can still get inconsistent seating depth with a regular die if you are over compressing as well So keep an eye on all of that stuff

[Dre_sa]

Researching suggests the crunch is ok, glad to have it confirmed. Stick powders don't have great packing efficiency, so they fill more of the case when not packing the powder down.

OAL is consistent, and holding. haven't noticed any bulging, signs are saying it's good to go. So I'll have to test them when the range opens up again.

When loading for precision, I have taken to vibration to pack powders better, but that's loading each round individually. This batch was done on a progressive press for bulk, drop tubing would be a challenge.

Thanks for the reply.

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[Unclenick]

Dre-Sa,

First, you have to realize different bullet construction affects pressure even when bullet weight matches. Up to 30%, according to Allan Jones. You are dealing with copper solids, which are harder to push into the rifling than a cup-and-core bullet is. Also, because copper is less dense than lead, they are long for their weight, especially with the large hollow point your bullets have. This means they use up more space in the case than a standard cup and core bullet does, which is why you are getting compression from such a light bullet.

The bottom line here is that you need to use load data appropriate for the type of bullet. The load data on Lehigh Defense site for that bullet also uses 42 grains to start but states that 45 grains is the maximum load with it.

Also, starting with a middle load is not a good strategy. Lots of folks do it and get away with it because 99% of the time or more it works out fine. But not every time. I've got three cases now, including one of my own, where a starting load proved to be already at maximum for the particular gun involved and going to the middle load produced sticky extraction or sticky bolt lift or popped an action open. No guns have blown up or anything that dramatic, but it isn't good for the gun's life expectancy to shoot many of those. It doesn't happen often, but it normally takes just a few rounds to test. Start with the bottom load and add powder in increments of up to 2% of the maximum load. In this case, that will be 0.9 grains per step. You will have just four loads. Check for pressure signs.

4064 does compress easily. Here's what drop tubes can do to pack it into the case.

[jmr40]

The brass you use matters too. 47 gr of 4064 might fit in Winchester brass, but overflow with another brand of brass.

[44 AMP]

The brass you use matters too. 47 gr of 4064 might fit in Winchester brass, but overflow with another brand of brass.

Unless they have changed the density of IMR 4064 a lot or reduced "normal" case capacity in .308 brass since the 70s, 47 gr of IMR 4064 will fit in every brand, and likely in GI brass as well.

I've loaded 52gr in Rem, Win, and DWM cases (110gr bullet) and it fits. It fills the case to the mouth, unless you settle it and then it nearly fills the case to the mouth, but it DOES fit.

And yes it gets compressed. IMR 4064 that I've used seems unaffected by some compression.

[Road_Clam]

I tried the droptube method with black powder as this is commonly needed to cram a LOT of powder and compress. Honestly I saw little if any differences in outcome of drop tube vs dropping right from my powder drop (maybe i'm doing it wrong ?). I will share a neat trick I learned if you need to get your powder to settle and that is to rest your filled casing up against the motor housing of a running bench grinder. The subtitle vibration from a typical bench grinder causes the power charge to vibrate and settle a bit and pretty quickly. Can't confirm this will work with 4064 matchstick powder but it does work nicely with 1.5F and 2F black powder.

[Unclenick]

The drop tube (note how much difference the long one made) causes the grains to bounce a lot on impact with the bottom of the case, and that tends to settle it the same as vibration does. A friend of mine recommends holding the case so the powder enters at a slight angle and swirls down the case for even more effect.

One of the authors of the 1995 Precision Shooting Reloading Guide had the experience that ammo he loaded to his recipe at home worked fine, but when he put the same load together at the range he got sticky bolt lift, indicating high pressure. He finally figured out that the vibration of driving the loads to the range was settling the powder enough to lower its relative burn rate.