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It seems as though IMR 4064 is gaining popularity and is more available. With LC or similar capacity brass (PPU) and the rod like configuration of the 4064 it looks as if the cases fill-up quickly, as compared to commercial brass. A charge of 42.5>43 grains of 4064 fills the case up near the mouth. Depending on the length/type of bullet there may be a chance of compressing the 4064 in the case. There is good info on this forum and can be found with a search using "IMR 4064 and LC Cases". Most of this info I have read and may have saved me from a serious mistake. Now I have some info but I also have a question or two.

When using a rod configured powder like 4064 is there a rule of thumb or precise data on the ratio of propellant and free (air) space inside the case after the bullet is seated. From all I have read compressing the propellant inside the case when seating the bullet is a No-No (over-pressure issues,..etc). Specifically, can you compress the 4064 a little without fear of over-pressures/malfunctions/damage to the rifle...etc? What is going to be the best for safety-vs-accuracy-vs-performance and the welfare of the M1A?

If some of you really talented and experienced re-loaders would like to impress folk like me, here's your chance. Thanks.
 

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Let me preface this by saying i'm assuming you have all your reloading stuff set up properly, scale calibrated right etc:

I've never had a problem using compressed loads in rifles. Pistols would be another story particularly powders like Trail boss you do NOT want to compress those. But in a rifle some powder kernel crunching is normal especially with the longer match bullets. A good starting point would be 42 grains 4064 with a 168 or 175 at 2.81" in lake ccity brass. You can fiddle with the seating depth or powder charge to fine tune from there but whatever you do only change one variable at a time.
 

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Long ago I ran across some military test data that concluded that the best fill ratio for a 30 - 06 cartridge, using IMR powder, was from 93 - 98 percent of the usable case volume once the bullet was seated. I have used that rule of thumb for my .308 cases ever since reading that info.

This fill ratio is dependent upon the volume of the case so case brands and lots make a difference. I usually check my case volumes (I use the water weight method as there is no real correlation between case weight and volume) from time to time and keep a record of the results. I don't like to use LC cases because their volumes limit my powder charge weights. Larger volume cases allow you more flexibility in regards to powder charge weights which, in turn, allow more flexibility with bullet weights. But, again, check the case volume before you use it, case volumes of about 56 grains of water are on the large side while some cases (certain LC years) hold as little as 53 grains of water. I like to use Lapua brass mainly because their volumes are pretty consistent (but they do vary from lot to lot too) and they are on the top end (about 56.4 grains of water). Several other, less expensive cases have about the same volume and so do some military cases (Venezuelan CAVIM being one of them and some of the more recent LC cases being another).

Bullets are also a factor in that the shape of the seated portion of the bullet will also change the amount of volume available. I have found that Hornady bullets seem to use up more case volume when they are seated which increases pressures and velocities a bit (I've tried to point this out when people claim that the Hornady manuals list lighter powder charge weights than other similar manuals...to no avail).
 

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Specifically, can you compress the 4064 a little without fear of over-pressures/malfunctions/damage to the rifle...etc? What is going to be the best for safety-vs-accuracy-vs-performance and the welfare of the M1A?
As to your question above, again, it depends on the case's volume. An older LC case with 53.4 grains of water capacity will produce pressures of around 58,000 PSI using a 175gr SMK seated to 2.82" COAL over 42 grains of IMR 4064. On the other hand, if the case has 56 grains of water capacity then the pressure will drop to around 51,700 PSI. Is the higher pressure safe? I believe it is but it will push the rifle harder than it was intended to be pushed, don't forget though that the rifle is tested with a proof load that produces something like 80 - 85000 PSI.
 

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You might also try using a drop tube to settle the powder grains better, which would minimize compression with the same load. I've found this especially helpful in reloading the 358 Win and others.
 
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Ram-

Curious as to the case capacities of current LC vintages? Do you have any data on 10-13?
Sorry, no. As I mentioned, I tend to stick with Lapua cases and I don't have much info in my records for LC cases except for LC 86 which was running about 53.5 grains of water. I do know that I've helped a few people recently that were using more recent LC cases (I just can't remember the years and since I didn't actually measure the cases myself I didn't add the volumes to my spreadsheet) that claimed to have more volume than that.
 
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Just a quick note on checking case volumes.
Check the capacity of the brass after it has been fired in your chamber and before resizing.
That's how I do it. Filled to the brim LC LR cases are 55 grains average. Lapua 56, winchester 57 for napkin math. Coincidentally if you load a max varget + 175smk load in winchester you'll hit pressure about 45 grains, in LC it is about 43-43.5. That's in line with the case capacity differences percentage wise.

I'm talking bolt guns and AR10s here. With the M1A I usually take about a grain off unless you have a vented gas plug.
 

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That's how I do it. Filled to the brim LC LR cases are 55 grains average. Lapua 56, winchester 57 for napkin math. Coincidentally if you load a max varget + 175smk load in winchester you'll hit pressure about 45 grains, in LC it is about 43-43.5. That's in line with the case capacity differences percentage wise.

I'm talking bolt guns and AR10s here. With the M1A I usually take about a grain off unless you have a vented gas plug.
Sounds like we are getting close to the same numbers for case volumes, that's good news.
 
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You may want to read this thread, has some good info

post1215754


It's about loading 190 HPBT....

Here is a load I have been using for years.
190 gr SRA HPBT
40Gr IMR 4064
CCI 200 Primer
LC Brass

As you can see I only use 40Gr IMR 4064, because of the 190gr bullet wt. This keeps the pressure down.

J R
 
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A few years back GI Brass sold Russian 4895. It was a stick powder that looked like 4895 but was intended for the Russian 7.62x54. When using this powder in a .308 with GI cases you almost couldn't get enough powder into the case it was so slow. I was putting 44.5 grains of this powder in, which would fill the case about 2/3 the way up the neck. I had to really crunch the 168 tip down and compressed the crap out of that powder. The gun functioned properly and the load was accurate.

Crunching ball powder is a no no....stick powder is OK to compress, (somewhat).
 
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I have a few LC years how high do you fill with water? too the mouth or shoulder where the neck meets?
For the entire case volume you use a case that has not been resized after having been fired. You weigh the empty case with the used primer in it. Then you fill the case to the top of the mouth, make the water as flat across the top as you can, weigh the water filled case. Subtract the weigh of the empty case from the weight of the water filled case and the difference is the weight of the water which is used to indicate the total volume of the case.
 

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In general, it is just the AMOUNT (weight) of powder in the case that determines the pressure. The AIR in the case doesn't particpate in the burning of the powder, and it doesn't act as a 'buffer' or 'shock absorber' - it's just empty space.

Using compressed powder charges can cause trouble in several ways:
1) having too much powder in the case (duh).
2) by having the compressed powder actually press the bullet back out a little bit, so the bullet doesn't fit the mag or chamber properly.
3) the 'compressing' might actually crush some of the powder rods, and that would increase their burn-rate, resulting in higher than expected pressure.

For 308Win with bullets 168 grain and heavier, I doubt there is a need to use a compressed load of 4064 to get good MV.
With lighter weight bullets, using a powder with faster burn-rate, or smaller grain size would be the solution.

Jay Kosta
Endwell NY USA
 

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As stated above use a drop tube. Another trick is to lightly tap the case before seating bullet to settle the powder. Work up loads and you wont have a problem with compressed powder loads.
BTW if you have to compress ball powder the odds are your load is to hot.
 

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For the entire case volume you use a case that has not been resized after having been fired. You weigh the empty case with the used primer in it. Then you fill the case to the top of the mouth, make the water as flat across the top as you can, weigh the water filled case. Subtract the weigh of the empty case from the weight of the water filled case and the difference is the weight of the water which is used to indicate the total volume of the case.
RAMMAC, check your PM........... as I find more Years, you will get them to fill in the blanks.
 

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For the entire case volume you use a case that has not been resized after having been fired. You weigh the empty case with the used primer in it. Then you fill the case to the top of the mouth, make the water as flat across the top as you can, weigh the water filled case. Subtract the weigh of the empty case from the weight of the water filled case and the difference is the weight of the water which is used to indicate the total volume of the case.
Using the above method, here is what I get for the following years. Once I got started I got on a roll as a side I didn't want too mow the lawn. That's the bulk of my brass hording 98% is milspec brass, everyone is welcome too use the info. I do have some commercial brass, but I'm kind of smoked out I will update when I have the energy..............

Lake City.
63 56.2
64 54.4
65 55.3
68 57.4
69 55.8
73 54
74 54.7
75 54.6
76 55.6
81 54.6
82 54.7
87 54.8
02 54.5
03 55
05 55

LC Match
65 54.5
66 55.3
72 55
79 54.9
81 55.4

LC Long Range
02 54
03 55.1
04 55
05 54.9
06 55.6

WRA
*1958 commercial case 59.2
66 55.3
68 55.2
70 55.6
84 55.2

RA
69 50.6 yea its small

IVI
68 55
69 55.6

TW
69 54.1

PMC 53.9

Odd balls
IK 85 55.4
PS 82 54.3
INDMIL 84 56.1
Frontier 56.2
PPU 55.8
CBC 54.5

Commercial
FC 54.8
REM-PETE 55.2
Win 308 57.0
 
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