I had performed some tests on brass to determine what effect the expander ball had on brass. See the link to the post here.
http://www.snipershide.com/forum/ubbthreads.php?ubb=showflat&Number=2007667#Post2007667
That test measured case lengthening. The test below attempts to confirm the previous findings as well as measure what effect the expander has on runout at the neck.
I used three 223 Remington Blackhills Match cases, fired twice, but resized the first time only. The test cases were fire formed to my rifle. The cases were cleaned, inside of the necks brushed, deprimed, and burrs removed that might interfere with measurement.
Tools and equipment used were a Forster C-Ax press, Redding FL die with floating carbide expander ball, Wilson/Sinclair case trimmer, Redding Neck Thickness measurement tool, Sinclair runout tool, Imperial case wax, Imperial neck lube media, and digital calipers. Setup included having the decapping pin end flush with the bottom of the die (when used), die set to provide shoulder dimension of 1.4285”, about .004” back from fire formed case.
All cases were trimmed to 1.7465". This is shorter than SAAMI spec minimum but done to ensure all edges of the case neck were touched by the trimmer. Cases were deburred and chamfered. The cases will be discarded following the test due to being under SAAMI spec length. All measurements shown are in inches and were checked a minimum of three times.
<span style="font-weight: bold">BASELINE</span> (inches)
Dimensions were as follows (inches).
<span style="text-decoration: underline">Case-----Length------Neck Wall--------Neck Runout----Neck</span>
Case #1 1.7465-----.0130 - .0170-----.0020------------.2540
Case #2 1.7465-----.0130 - .0150-----.0060------------.2545
Case #3 1.7465-----.0110 - .0130-----.0010------------.2535
Case #1 and #2 have really big neck thickness variations. I believe the neck was slightly damaged upon ejection by the AR15, either on the way out or hitting the pavement. Hard to say. But, I do not think the neck thickness readings are truly accurate. My Redding measuring tool does not allow me to reach further inside the neck to check other places on the neck.
Neck runout could be due to poor neck concentricity with the case body or neck thickness variation, or a combination of both. Without a neck turning tool to make neck thickness consistent, I can not know.
<span style="font-weight: bold">TEST #1 – RESIZE W/NO EXPANDER</span>
<span style="text-decoration: underline">Case-----Length-----Increase--------Neck Wall--------Neck Runout-------Neck O.D.</span>
Case #1 1.7510-----.0045------------N/A*-------------.0005---------------.2400
Case #2 1.7515-----.0050------------N/A*-------------.0008---------------.2400
Case #3 1.7530-----.0065------------N/A*-------------.0005---------------.2400
*Unable to measure due to unexpanded neck squeezed down to a size that would not fit over Redding Neck Wall measurement mandrel.
This test reveals that resizing the brass, without an expander ball causes brass to grow in length. The average here is .0053, consistent with the previous test results shown in the aforementioned post. Neck runout is very low. Test #2 will reveal what happens when an expander ball is run through.
<span style="font-weight: bold">
TEST #2 – RESIZE BRASS FROM TEST #1 W/EXPANDER</span>
<span style="text-decoration: underline">Case-----Length------Increase-------------Neck Wall-----------Neck Runout--------Neck </span>
Case #1 1.7500------Minus .0010--------.0115 - .0120-------.0030----------------.2455
Case #2 1.7505------Minus .0010.-------.0120 - .0125-------.0035----------------.2455
Case #3 1.7510------Minus .0020--------.0110 - .0125-------.0050----------------.2455
Conclusions and Observations:
1) Toss out neck wall thickness in BASELINE as I believe the big variations were due to small defects in the brass. Neck wall thickness variation in BASELINE was probably the same or close to what was reported in Test #2.
2) Brass DOES grow in length when full length resized, with or without an expander. For this test, an average of .0053”, when resized from a fire formed state.
3) Using the expander adds neck runout. The cases used to test this in Test #2 were already FL resized in TEST #1, with the expander being the only force acting on the brass. This action results in an average runout at the neck of .0038”. Note however that without the expander, the die did an excellent job of sizing the neck. Runout was less than .001”, with any neck wall thickness variation pushed to the interior of the neck. It is important to note that the expander will push that neck wall thickness variation to the outside where it is picked up as runout. Therefore, the measured average runout with the expander of .0038” includes both neck wall thickness variation and concentricity errors. The only way to know for sure how much the expander really is affecting the runout of the neck is to make sure the neck has consistent wall thickness by turning the neck and redoing the test. For another day!
4) I can not explain how the brass ended up slightly shorter in Test #2.
5) The neck edge after full length resizing with and without the expander ball sometimes was no longer square with the case. This was proven by slowly edging a trimmer blade onto the case neck, and noting it did not touch down everywhere at once. This can only be because as the case lengthens, it does not do so evenly, with one side or part of the side of the case and or neck elongating a bit more than elsewhere. I would expect this to be on the thin side of the case, but did not measure that.
I hope this has been informative, even if I am very new to all of this, and if I made any mistakes any testing or conclusions, please let me know so I can correct. However, at this point I am running out of fireformed brass! Time to reload and make some more test cases!
- Phil
http://www.snipershide.com/forum/ubbthreads.php?ubb=showflat&Number=2007667#Post2007667
That test measured case lengthening. The test below attempts to confirm the previous findings as well as measure what effect the expander has on runout at the neck.
I used three 223 Remington Blackhills Match cases, fired twice, but resized the first time only. The test cases were fire formed to my rifle. The cases were cleaned, inside of the necks brushed, deprimed, and burrs removed that might interfere with measurement.
Tools and equipment used were a Forster C-Ax press, Redding FL die with floating carbide expander ball, Wilson/Sinclair case trimmer, Redding Neck Thickness measurement tool, Sinclair runout tool, Imperial case wax, Imperial neck lube media, and digital calipers. Setup included having the decapping pin end flush with the bottom of the die (when used), die set to provide shoulder dimension of 1.4285”, about .004” back from fire formed case.
All cases were trimmed to 1.7465". This is shorter than SAAMI spec minimum but done to ensure all edges of the case neck were touched by the trimmer. Cases were deburred and chamfered. The cases will be discarded following the test due to being under SAAMI spec length. All measurements shown are in inches and were checked a minimum of three times.
<span style="font-weight: bold">BASELINE</span> (inches)
Dimensions were as follows (inches).
<span style="text-decoration: underline">Case-----Length------Neck Wall--------Neck Runout----Neck</span>
Case #1 1.7465-----.0130 - .0170-----.0020------------.2540
Case #2 1.7465-----.0130 - .0150-----.0060------------.2545
Case #3 1.7465-----.0110 - .0130-----.0010------------.2535
Case #1 and #2 have really big neck thickness variations. I believe the neck was slightly damaged upon ejection by the AR15, either on the way out or hitting the pavement. Hard to say. But, I do not think the neck thickness readings are truly accurate. My Redding measuring tool does not allow me to reach further inside the neck to check other places on the neck.
Neck runout could be due to poor neck concentricity with the case body or neck thickness variation, or a combination of both. Without a neck turning tool to make neck thickness consistent, I can not know.
<span style="font-weight: bold">TEST #1 – RESIZE W/NO EXPANDER</span>
<span style="text-decoration: underline">Case-----Length-----Increase--------Neck Wall--------Neck Runout-------Neck O.D.</span>
Case #1 1.7510-----.0045------------N/A*-------------.0005---------------.2400
Case #2 1.7515-----.0050------------N/A*-------------.0008---------------.2400
Case #3 1.7530-----.0065------------N/A*-------------.0005---------------.2400
*Unable to measure due to unexpanded neck squeezed down to a size that would not fit over Redding Neck Wall measurement mandrel.
This test reveals that resizing the brass, without an expander ball causes brass to grow in length. The average here is .0053, consistent with the previous test results shown in the aforementioned post. Neck runout is very low. Test #2 will reveal what happens when an expander ball is run through.
<span style="font-weight: bold">
TEST #2 – RESIZE BRASS FROM TEST #1 W/EXPANDER</span>
<span style="text-decoration: underline">Case-----Length------Increase-------------Neck Wall-----------Neck Runout--------Neck </span>
Case #1 1.7500------Minus .0010--------.0115 - .0120-------.0030----------------.2455
Case #2 1.7505------Minus .0010.-------.0120 - .0125-------.0035----------------.2455
Case #3 1.7510------Minus .0020--------.0110 - .0125-------.0050----------------.2455
Conclusions and Observations:
1) Toss out neck wall thickness in BASELINE as I believe the big variations were due to small defects in the brass. Neck wall thickness variation in BASELINE was probably the same or close to what was reported in Test #2.
2) Brass DOES grow in length when full length resized, with or without an expander. For this test, an average of .0053”, when resized from a fire formed state.
3) Using the expander adds neck runout. The cases used to test this in Test #2 were already FL resized in TEST #1, with the expander being the only force acting on the brass. This action results in an average runout at the neck of .0038”. Note however that without the expander, the die did an excellent job of sizing the neck. Runout was less than .001”, with any neck wall thickness variation pushed to the interior of the neck. It is important to note that the expander will push that neck wall thickness variation to the outside where it is picked up as runout. Therefore, the measured average runout with the expander of .0038” includes both neck wall thickness variation and concentricity errors. The only way to know for sure how much the expander really is affecting the runout of the neck is to make sure the neck has consistent wall thickness by turning the neck and redoing the test. For another day!
4) I can not explain how the brass ended up slightly shorter in Test #2.
5) The neck edge after full length resizing with and without the expander ball sometimes was no longer square with the case. This was proven by slowly edging a trimmer blade onto the case neck, and noting it did not touch down everywhere at once. This can only be because as the case lengthens, it does not do so evenly, with one side or part of the side of the case and or neck elongating a bit more than elsewhere. I would expect this to be on the thin side of the case, but did not measure that.
I hope this has been informative, even if I am very new to all of this, and if I made any mistakes any testing or conclusions, please let me know so I can correct. However, at this point I am running out of fireformed brass! Time to reload and make some more test cases!
- Phil
