Compressed loads

bungiex88 · March 4, 2016, 03:17 PM

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

wpsdlrg · March 4, 2016, 03:36 PM

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.

bungiex88 · March 4, 2016, 03:55 PM

When I take them to the range and work up I'll check all my cases. I shoot through a chrony to to make sure it's good

**Unclenick** · March 4, 2016, 04:27 PM

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.

Gunplummer · March 4, 2016, 05:13 PM

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.

bungiex88 · March 5, 2016, 12:16 AM

So should I not fire those rounds I made that were close to maximum load that I did load or should I just be careful when shooting and checking my velocity every time I step up and pressure signs

Gunplummer · March 5, 2016, 04:16 AM

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.

hartcreek · March 5, 2016, 04:22 AM

If I remember right 4064 is like short cut angel hair pasta. Did you tap your cases? Often this kinda long kernal powder will drop in the case with voids. When this happens I tap the side of the case to settle it a bit.

flashhole · March 5, 2016, 08:17 AM

I use the flat on the metal shaft of a vibrating toothbrush to settle powder. Just run it up and down the side of the case a few times. You will be surprised how much it settles.

1100 tac · March 5, 2016, 08:34 AM

Or a drop tube.

Gunplummer · March 5, 2016, 09:04 PM

They don't call it "Settled loads". It is compressed loads. Really.

David R · March 5, 2016, 09:10 PM

Long drop tube works f or me.

David

Ben Dover · March 5, 2016, 10:52 PM

Easy solution?

Switch to a spherical powder like H335, BL-C2, etc.

March 4, 2016, 03:17 PM	#1
bungiex88 Senior Member Join Date: May 14, 2015 Location: central pa Posts: 264	Compressed loads 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 __________________ Life is to short to give a darn

March 4, 2016, 03:55 PM	#3
bungiex88 Senior Member Join Date: May 14, 2015 Location: central pa Posts: 264	When I take them to the range and work up I'll check all my cases. I shoot through a chrony to to make sure it's good __________________ Life is to short to give a darn

March 4, 2016, 04:27 PM	#4
Unclenick Staff Join Date: March 4, 2005 Location: Ohio Posts: 21,063	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. __________________ Gunsite Orange Hat Family Member CMP Certified GSM Master Instructor NRA Certified Rifle Instructor NRA Benefactor Member and Golden Eagle

March 5, 2016, 12:16 AM	#6
bungiex88 Senior Member Join Date: May 14, 2015 Location: central pa Posts: 264	So should I not fire those rounds I made that were close to maximum load that I did load or should I just be careful when shooting and checking my velocity every time I step up and pressure signs __________________ Life is to short to give a darn Last edited by bungiex88; March 5, 2016 at 01:02 AM.

March 5, 2016, 08:17 AM	#9
flashhole Senior Member Join Date: February 9, 2005 Location: Owego, NY Posts: 2,000	I use the flat on the metal shaft of a vibrating toothbrush to settle powder. Just run it up and down the side of the case a few times. You will be surprised how much it settles. __________________ ,,, stupidity comes to some people very easily. 8/22/2017 my wife in a discussion about Liberals. Are you ready for civil war?

March 4, 2016, 03:36 PM	#2
wpsdlrg Senior Member Join Date: August 18, 2009 Posts: 826	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.

March 4, 2016, 05:13 PM	#5
Gunplummer Senior Member Join Date: March 11, 2010 Location: South East Pa. Posts: 3,364	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.

March 5, 2016, 04:16 AM	#7
Gunplummer Senior Member Join Date: March 11, 2010 Location: South East Pa. Posts: 3,364	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.

March 5, 2016, 04:22 AM	#8
hartcreek Junior member Join Date: April 22, 2014 Location: Washington Posts: 1,549	If I remember right 4064 is like short cut angel hair pasta. Did you tap your cases? Often this kinda long kernal powder will drop in the case with voids. When this happens I tap the side of the case to settle it a bit.

March 5, 2016, 08:34 AM	#10
1100 tac Senior Member Join Date: February 7, 2012 Posts: 299	Or a drop tube.

March 5, 2016, 09:04 PM	#11
Gunplummer Senior Member Join Date: March 11, 2010 Location: South East Pa. Posts: 3,364	They don't call it "Settled loads". It is compressed loads. Really.

March 5, 2016, 09:10 PM	#12
David R Senior Member Join Date: January 2, 2015 Location: The swamps of WNY Posts: 753	Long drop tube works f or me. David

March 5, 2016, 10:52 PM	#13
Ben Dover Senior Member Join Date: April 11, 2013 Location: High up in the Rocky Moun Posts: 665	Easy solution? Switch to a spherical powder like H335, BL-C2, etc. __________________ The soldier's pack is not so heavy a burden as the prisoner's chains. Dwight Eisenhower It is very important what a man stands for. But it is far more important what a man refuses to stand for.