Reloading 308 with imr4064 and 168gr hornady amax. Now I reloaded 165 gr nosler with same powder and didn't notice it but I was making 3 rounds and working up to max to go out and test and when I got half way I notice the loads were becoming compressed to the point it was changing my seating depth a little. Is this normal. The only thing I changed from the nosler and hornady was I am now using lake city brass which I know is a little smaller. The suggested load for both bullets were the same of 4064 42 to 46 gr
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Compressed loads
- Thread starter bungiex88
- Start date
Differences in the length of the bullet used can cause this - I think that is what you are probably experiencing. Compare your (previously used and currently used) bullets for length - that will probably tell the tale.
As for whether it is "normal"....it just IS, with that combination. "Normal" it might or might not be, depending on your case volume. What you need to know is whether the load is SAFE. As long as you are NOT loading above the published data for that particular combination, or seating the bullet too deeply, the load should be safe.
Compressed loads can be tricky, however, depending on the amount of compression. It is most always a good idea, with a compressed load, to use a firm taper crimp on the finished cartridge, to ensure that the COL stays the same as you set it. If you are getting a lot of powder compression, such that the seated bullet does not want to stay in place.....I'd recommend going to a different bullet, or seating less deeply (if possible). As I said, compressed loads can be tricky. Your cases (with a bit smaller volume than others perhaps... combined with a long bullet, may just make for an impractical load) - though not necessarily unsafe. So, for practical reasons, you might need to change components.
As for whether it is "normal"....it just IS, with that combination. "Normal" it might or might not be, depending on your case volume. What you need to know is whether the load is SAFE. As long as you are NOT loading above the published data for that particular combination, or seating the bullet too deeply, the load should be safe.
Compressed loads can be tricky, however, depending on the amount of compression. It is most always a good idea, with a compressed load, to use a firm taper crimp on the finished cartridge, to ensure that the COL stays the same as you set it. If you are getting a lot of powder compression, such that the seated bullet does not want to stay in place.....I'd recommend going to a different bullet, or seating less deeply (if possible). As I said, compressed loads can be tricky. Your cases (with a bit smaller volume than others perhaps... combined with a long bullet, may just make for an impractical load) - though not necessarily unsafe. So, for practical reasons, you might need to change components.
Hornady cases I've seen weigh around 155 grains or sometimes less. Lake City cases weigh close to 180 grains. If the brass and the head dimensions were identical, this would correspond to almost three grains difference in case water overflow capacity. Figure that will, in turn, correspond to about 1.8 to 2.0 grains less powder in the Lake City cases to reach the same peak pressure.
A better way to check this, since the portions of the brass in the heads and side walls differ and head tolerances differ, making a brass weight comparison inexact for determining capacity, is to measure the actual difference. You fire the cases in your chamber, since the case expands before pressure peaks, and therefore the as-fired size it what determines pressure. This is true in any gun firing at about 30,000 psi peak pressure or higher. Leave the spent primers in place. Trim them the cases to the same length. Weigh the empty cases. Fill the cases with water level with the case mouth. No meniscus, no drops on the outside, no air bubbles inside. Weight them again. Subtract the dry weights of the cases. That will give you weight of water that occupied each case. If the water was at room temperature, multiply the results by 0.997 to compensate for the fact water is a little less dense at room temperature than it is at it's most dense temperature (about 39°F).
The difference in those weights is what you want to know. The powder charge will differ by about 0.62 to about 0.72 grains for each grain of difference in powder capacity, depending on the powder. 4064 is less sensitive to charge weigh variations than some, so you can use the smaller number with it.
A better way to check this, since the portions of the brass in the heads and side walls differ and head tolerances differ, making a brass weight comparison inexact for determining capacity, is to measure the actual difference. You fire the cases in your chamber, since the case expands before pressure peaks, and therefore the as-fired size it what determines pressure. This is true in any gun firing at about 30,000 psi peak pressure or higher. Leave the spent primers in place. Trim them the cases to the same length. Weigh the empty cases. Fill the cases with water level with the case mouth. No meniscus, no drops on the outside, no air bubbles inside. Weight them again. Subtract the dry weights of the cases. That will give you weight of water that occupied each case. If the water was at room temperature, multiply the results by 0.997 to compensate for the fact water is a little less dense at room temperature than it is at it's most dense temperature (about 39°F).
The difference in those weights is what you want to know. The powder charge will differ by about 0.62 to about 0.72 grains for each grain of difference in powder capacity, depending on the powder. 4064 is less sensitive to charge weigh variations than some, so you can use the smaller number with it.
Gunplummer
New member
I don't remember what I was reloading, but I tried a compressed load. I rarely crimp bullets and the bullets were backing out AFTER I was done loading them. That was the end of compressed loads for me.
Gunplummer
New member
Not sure what your complaint is here. In the OP, you were worried about seating depth. If the compressed loads are slowly pushing the bullet back out of the case, the bullet may be jammed into the rifling when you chamber it. Some of my bullets had Really backed out of the case. I pulled them and started over. Up to you.
Gunplummer
New member
They don't call it "Settled loads". It is compressed loads. Really.