So, I went a couple of steps further in determining what the case volume is on my cases (All Lake City once fired) and popped out the spent primers on several fire formed (fired in my rifle) cases. I then plugged the flash hole with glycerin soap because it is slightly clear and allowed me to shine a light below the primer pocket and see into the case mouth so I could remove any extruded soap from inside the case. The idea was to completely plug the flash hole, but not take up any space in the case, so I could get a 100% accurate measurement of the case volume using distilled water.
The average case volume after measuring 10 cases this way was 30.6 grains of water.
I decided to test 3 different powders this weekend:
Ramshot TAC
Ramshot X-Terminator
Hodgdon BLC-2
The temperature out at my range was slated to be between 83-85f on Saturday, so I set QuickLoad up accordingly and loaded all 3 powders for 85f
I loaded up 20 cartridges (each) in a 5 rung ladder for the TAC and the BLC-2. Each rung was marked with a different color sharpie on the bottom of the case for easy identification as seen in the picture below:
Here is how the ladder looked as far a charge volume(s):
TAC: (1) 25.5 gr. (2) 25.9 gr. (3) 26.4 gr. (4) 26.9 gr. (5) 27.3 gr.
BLC-2: (1) 26.6 gr. (2) 27.0 gr. (3) 27.5 gr. (4) 28.0 gr. (5) 28.5 gr.
For the X-Terminator, I did NOT load up a ladder. I loaded up a box of cartridges using a safe medium load to test with some 69 gr. PRVI HPBT bullets and ran them across the chrono just to see where the stood, more on that load at the end of this post..
All of the loads in both the TAC and BLC-2 ladders were built using Montana Gold 55gr. FMJ-BT bullets. I call these bullets boat tails, even though Montan Gold does not list them as such, but they do in fact have a very slight boat tail design which I measured and entered into QL. Bullets were seated for a COAL of 2.255" No fewer than half of the finished cartridges were also checked with a comparator with results not exceeding .003". I use a competition seating die on one of my Dillon 1050's. ALL cases were once fired, LC-05 headstamp, completely prepped using an RCBS case prep station.
I had 2 test rifles with me (AR-15's) that I personally built.
(1) Satern 16" barrel, 1:8 Wylde chambered .
(2) FN 16" barrel, 1:7 NATO chambered .
The chrono was set up approximately 10 feet in front of the rifle(s) using the infra red sky screens. It was a crystal clear day, and the weather web was right on the money, as it was 85f with a slight breeze blowing when the testing commenced.
The idea going in to this test was to shoot 10 rounds from each rung through each of the (2) rifles across the chrono during the hottest part of the day to limit temperature change variations.
Here is a screen grab of the chrono download for the TAC ladder. The data in the far left column indicates the gun used: "B-16" = Billet rifle with Satern barrel and "M-S 16" = Mil-Spec rifle with FN barrel. That info is followed by the bullet info. The cell directly below the rifle and bullet designation indicates the powder charge used for that row (rung) of data. Finally, the RED numbers at the far right of each row indicate the difference in velocity between QL's predicted and the AVERAGE observed velocities <x>. The number to the right of that indicates the percentage difference between predicted and observed (average) velocities:
The worst of this bunch is seen in ROW 10 (TAC 26.9 gr.), and produced a 7.30% difference in predicted vs observed velocity.
Also noteworthy is that the difference between the "B-16" and the "M-S 16" rifles is really small. Furthermore, TAC @ 26.9 gr. seems to show a high spike in velocity across both rifles, but when the charge is increased to 27.3 gr. the difference spike seems to wane. Unfortunately, I was not able to get a full 10 shot reading from the M-S 16 rifle for the 27.3 gr. TAC load so that claim could be debated..
Next up was the BLC-2 ladder.
I decided NOT to shoot BLC-2 through both rifles since the previous testing indicated a variation between rifles that I would call negligible. Instead I focused on getting the data from the B-16 rifle (Satern/Wylde) exclusively.
The chrono data is seen below:
Again, you can see that the predicted and observed velocities are within 5% which is a good thing as far as I am concerned, but I would love to hear some feedback from those of you who have an educated opinion on all of this. It is my understanding that powder manufacturers are required to re-designate a particular powder if Ba (difference) values exceed 10%. I am wondering how many of them actually adhere to this standard? Experience from my previous outing would indicate that Accurate ignores this rule.
Finally, here is the data from Ramshot X-Terminator:
I used the same (B-16) rifle for the test, and oddly enough, the observed velocity was BELOW the predicted velocity by a little bit. I would call this particular test a near perfect prediction from QL for this particular load:
Things to consider:
(1) Every single cartridge referenced in this test was loaded during the same Friday evening (the day before the test).
(2) Every single cartridge referenced in this test was prepped exactly the same way on the RCBS case prep station.
(3) Every single cartridge referenced in this test was loaded on the same press (Dillon 1050), using the same powder measure, scale, calipers, etc.
(4) ALL cases used in this test were trimmed to 1.754" +/- .002" . Any case found to be outside the (+.002" / -0.000") was rejected and not used.
(5) ALL projectiles were individually weighed to fall within a .1 gr. tolerance.
YES it took me several hours to do all of this, but I wanted good data and strive'd to eliminate as many variables as I could.
It would be nice to hear what you think about how to get closer to achieving observed vs predicted velocity nirvana. Where do I go from here?
Thank you for your input.
The average case volume after measuring 10 cases this way was 30.6 grains of water.
I decided to test 3 different powders this weekend:
Ramshot TAC
Ramshot X-Terminator
Hodgdon BLC-2
The temperature out at my range was slated to be between 83-85f on Saturday, so I set QuickLoad up accordingly and loaded all 3 powders for 85f
I loaded up 20 cartridges (each) in a 5 rung ladder for the TAC and the BLC-2. Each rung was marked with a different color sharpie on the bottom of the case for easy identification as seen in the picture below:
Here is how the ladder looked as far a charge volume(s):
TAC: (1) 25.5 gr. (2) 25.9 gr. (3) 26.4 gr. (4) 26.9 gr. (5) 27.3 gr.
BLC-2: (1) 26.6 gr. (2) 27.0 gr. (3) 27.5 gr. (4) 28.0 gr. (5) 28.5 gr.
For the X-Terminator, I did NOT load up a ladder. I loaded up a box of cartridges using a safe medium load to test with some 69 gr. PRVI HPBT bullets and ran them across the chrono just to see where the stood, more on that load at the end of this post..
All of the loads in both the TAC and BLC-2 ladders were built using Montana Gold 55gr. FMJ-BT bullets. I call these bullets boat tails, even though Montan Gold does not list them as such, but they do in fact have a very slight boat tail design which I measured and entered into QL. Bullets were seated for a COAL of 2.255" No fewer than half of the finished cartridges were also checked with a comparator with results not exceeding .003". I use a competition seating die on one of my Dillon 1050's. ALL cases were once fired, LC-05 headstamp, completely prepped using an RCBS case prep station.
I had 2 test rifles with me (AR-15's) that I personally built.
(1) Satern 16" barrel, 1:8 Wylde chambered .
(2) FN 16" barrel, 1:7 NATO chambered .
The chrono was set up approximately 10 feet in front of the rifle(s) using the infra red sky screens. It was a crystal clear day, and the weather web was right on the money, as it was 85f with a slight breeze blowing when the testing commenced.
The idea going in to this test was to shoot 10 rounds from each rung through each of the (2) rifles across the chrono during the hottest part of the day to limit temperature change variations.
Here is a screen grab of the chrono download for the TAC ladder. The data in the far left column indicates the gun used: "B-16" = Billet rifle with Satern barrel and "M-S 16" = Mil-Spec rifle with FN barrel. That info is followed by the bullet info. The cell directly below the rifle and bullet designation indicates the powder charge used for that row (rung) of data. Finally, the RED numbers at the far right of each row indicate the difference in velocity between QL's predicted and the AVERAGE observed velocities <x>. The number to the right of that indicates the percentage difference between predicted and observed (average) velocities:
The worst of this bunch is seen in ROW 10 (TAC 26.9 gr.), and produced a 7.30% difference in predicted vs observed velocity.
Also noteworthy is that the difference between the "B-16" and the "M-S 16" rifles is really small. Furthermore, TAC @ 26.9 gr. seems to show a high spike in velocity across both rifles, but when the charge is increased to 27.3 gr. the difference spike seems to wane. Unfortunately, I was not able to get a full 10 shot reading from the M-S 16 rifle for the 27.3 gr. TAC load so that claim could be debated..
Next up was the BLC-2 ladder.
I decided NOT to shoot BLC-2 through both rifles since the previous testing indicated a variation between rifles that I would call negligible. Instead I focused on getting the data from the B-16 rifle (Satern/Wylde) exclusively.
The chrono data is seen below:
Again, you can see that the predicted and observed velocities are within 5% which is a good thing as far as I am concerned, but I would love to hear some feedback from those of you who have an educated opinion on all of this. It is my understanding that powder manufacturers are required to re-designate a particular powder if Ba (difference) values exceed 10%. I am wondering how many of them actually adhere to this standard? Experience from my previous outing would indicate that Accurate ignores this rule.
Finally, here is the data from Ramshot X-Terminator:
I used the same (B-16) rifle for the test, and oddly enough, the observed velocity was BELOW the predicted velocity by a little bit. I would call this particular test a near perfect prediction from QL for this particular load:
Things to consider:
(1) Every single cartridge referenced in this test was loaded during the same Friday evening (the day before the test).
(2) Every single cartridge referenced in this test was prepped exactly the same way on the RCBS case prep station.
(3) Every single cartridge referenced in this test was loaded on the same press (Dillon 1050), using the same powder measure, scale, calipers, etc.
(4) ALL cases used in this test were trimmed to 1.754" +/- .002" . Any case found to be outside the (+.002" / -0.000") was rejected and not used.
(5) ALL projectiles were individually weighed to fall within a .1 gr. tolerance.
YES it took me several hours to do all of this, but I wanted good data and strive'd to eliminate as many variables as I could.
It would be nice to hear what you think about how to get closer to achieving observed vs predicted velocity nirvana. Where do I go from here?
Thank you for your input.