Hey all, So i searched about this and didn't find the answer i was looking for. I have 28 nosler brass. One lot weighs 262 +/- 1 grain. Then i have brass that was 282 +/- 2 grains. The 282 grain brass holds 101 grains of water. The 262 grain brass holds 102.6 grains water. These are made by nosler. Do you think that they will differ with point of impact and velocity/pressure when each are to the same dimensions? thanks
Brass weight capacity
- Thread starter krhuntin
- Start date
Try searching in the reloading section for weight/volume discussions.
Your numbers indicate about 12.5 to:1 brass to water difference (20gr brass:1.6gr water). How accurate were your measurements?
Weight measurement accuracy close to your final powder accuracy would give a better view of power volume as it compares to water volume. Getting meniscus to 0.1 grain or better takes care.
Your 1.6 grains of water difference is about a 2% variance in volume. Might matter at load densities above 80-85%
I would definitely segregate brass with that big a difference.
Getting meniscus to 0.1 grain or better takes care.
What does the capacity difference LOOK like in your cases.
Here's what 1.6gr capacity difference looks like in a much smaller case (22 Nolser, 22 Nosgar).
This is about 1.6gr of powder capacity for a 15gr brass difference.
That's about 9.4 to 1 brass to powder but the 22 Nosgar case has a 6.8 type rim (more brass in the head) and 22 Nosler has a 5.56 type rim.
Your numbers indicate about 12.5 to:1 brass to water difference (20gr brass:1.6gr water). How accurate were your measurements?
Weight measurement accuracy close to your final powder accuracy would give a better view of power volume as it compares to water volume. Getting meniscus to 0.1 grain or better takes care.
Your 1.6 grains of water difference is about a 2% variance in volume. Might matter at load densities above 80-85%
I would definitely segregate brass with that big a difference.
Getting meniscus to 0.1 grain or better takes care.
What does the capacity difference LOOK like in your cases.
Here's what 1.6gr capacity difference looks like in a much smaller case (22 Nolser, 22 Nosgar).
This is about 1.6gr of powder capacity for a 15gr brass difference.
That's about 9.4 to 1 brass to powder but the 22 Nosgar case has a 6.8 type rim (more brass in the head) and 22 Nosler has a 5.56 type rim.
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That 1.6 grs difference makes a significant difference in my .308 cases and should make a difference too with your .28 Nosler (not quite as much difference as with the .308, but will definitely effects the velocity/pressure).
Ned Ludd
Silver $$ Contributor
As Straightshooter 1 noted, you're looking at approximately a 1.5% difference in case volume. Multiplying that difference by a random velocity value of 3000 fps yields an approximate difference of 48 fps. This is a very crude method to estimate the effects of differential case volume. Nonetheless, it can be used as a very rough guide to estimate whether the effective difference in case volume is sufficient that a change in charge weight might be necessary to maintain similar velocity to the load in the previous set of cases.
There are several ways you could approach this. Perhaps the simplest would be to load a charge weight that is reduced by a few tenths grains to half a grain of powder in the cases with smaller internal volume for safety/pressure reasons, then determine actual velocity. Chances are the velocity will be fairly close to that achieved in the larger internal volume cases with a slightly higher charge weight. At any rate, it should be close enough that you will then know pretty well what charge weight range to test in order to reproduce the original velocity in the new brass.
Note: I can't tell from your post which case volume represents the newer brass. I'm assuming the newer Lot of brass has the smaller capacity. If it is the opposite (i.e. the newer cases have the larger internal volume, you can simply load up the previous charge weight and re-measure velocity. In that case, the charge weight will already be effectively reduced as compared to the previous brass internal volume. The bottom line is that a change in internal case volume certainly change velocity/pressure, and how a load performs, if the change is large enough. If the new Lot of brass has less capacity, reduce the charge weight a bit for safety reasons, then determine velocity. I have no way of knowing where the previous load was on the pressure curve for the .28 Nosler, but there's no reason to push the envelope for such a simple test. All you're trying to do is be sure the new [test] load won't potentially be over-pressure, then determine velocity to establish a reference point for comparison to the old load. For a change in case volume of that magnitude, you could probably make a very reasonable estimate in terms of how it might affect charge weight/pressure/velocity using QuickLoad or GRT without ever firing a shot. However, simply establishing velocity in the new brass will achieve the same goal with a minimum of time/effort.
There are several ways you could approach this. Perhaps the simplest would be to load a charge weight that is reduced by a few tenths grains to half a grain of powder in the cases with smaller internal volume for safety/pressure reasons, then determine actual velocity. Chances are the velocity will be fairly close to that achieved in the larger internal volume cases with a slightly higher charge weight. At any rate, it should be close enough that you will then know pretty well what charge weight range to test in order to reproduce the original velocity in the new brass.
Note: I can't tell from your post which case volume represents the newer brass. I'm assuming the newer Lot of brass has the smaller capacity. If it is the opposite (i.e. the newer cases have the larger internal volume, you can simply load up the previous charge weight and re-measure velocity. In that case, the charge weight will already be effectively reduced as compared to the previous brass internal volume. The bottom line is that a change in internal case volume certainly change velocity/pressure, and how a load performs, if the change is large enough. If the new Lot of brass has less capacity, reduce the charge weight a bit for safety reasons, then determine velocity. I have no way of knowing where the previous load was on the pressure curve for the .28 Nosler, but there's no reason to push the envelope for such a simple test. All you're trying to do is be sure the new [test] load won't potentially be over-pressure, then determine velocity to establish a reference point for comparison to the old load. For a change in case volume of that magnitude, you could probably make a very reasonable estimate in terms of how it might affect charge weight/pressure/velocity using QuickLoad or GRT without ever firing a shot. However, simply establishing velocity in the new brass will achieve the same goal with a minimum of time/effort.
6bra1k is right about not shooting those two lots together. You may not see a difference at 100 yds, but the Nosler is a long distance round and you will see the ES and SD in more vertical the farther you shoot.
I don't think you have to segregate within your lots any finer than the +/-1. The Nosler case probably weighs twice what a 6bra does with 3 times the capacity, making your sorting finer in that way.
I agree with Ned and Straight, probably because they explain things so I can understand! lol
I don't think you have to segregate within your lots any finer than the +/-1. The Nosler case probably weighs twice what a 6bra does with 3 times the capacity, making your sorting finer in that way.
I agree with Ned and Straight, probably because they explain things so I can understand! lol
Yes......
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