PN45 Pressure Trace N110 & 250gr. SST
Feb 3, 2011 16:17:40 GMT -5
Post by TGinPA on Feb 3, 2011 16:17:40 GMT -5
PN45 Pressure Trace N110 & 250gr resized SST
Today was a challenge. Dave W. had asked about pressure traces using N110 as a single powder sabotless. Because the powder column was so short, I decided to use a Savage breech plug to better position the powder under the sensor. Also, I thought it best to add another sensor to my barrel closer to the breech plug (.596 in. from BP snout). After getting set up and connected to the new sensor, I fired a test load with a known pressure from previous tests. The first curve checked out fine and I set up to measure a load (N110 40 gr ,250 gr resized SST). Pressures were not consistent and I thought that maybe the new sensor was bad. I switched back to the old sensor and results were no better. At that point I found that one of the tiny female connector pins connecting the shielded cord to the sensor had partially backed out of the plastic connector, giving me an inconsistent connection to the sensor. After pushing the pin back into the plastic connector, I recorded a single trace (N110 40gr 250gr SST) which gave a velocity of 2388 fps and the upper of the two pressure traces shown below. I then ran a second series of one load (N110 42 gr., 250 SST, 3 shots). Somehow, I managed to erase the second series before I was able to transfer it onto my desktop. I had recorded the average peak pressure 41k psi and velocity (2425fps, 3 shots average) before I lost the trace. Back to the drawing board, I re-set up and recorded one more single trace of the 42gr load which is shown as the lower trace below and is consistent with what I saw on the erased pressure traces. What I think I can conclude from this is that 42 gr. of N110 generates velocities which might be useful in a single powder hunting load using a 250 gr. bullet at pressures which are close to max in a PN45 barrel. Interestingly, according to Edge, QuickLoad estimates 5k psi higher pressures for the 42 gr. load than what I measured. Could this difference be due to pressure buildup due to bullet deformation into the lands in a cartridge load? The loads I tested today seemed safe in my gun under the conditions of the tests, but may not be so under other conditions.
Computer: Dell Inspiron Mini Notebook Gage and Module Manufacturer = RSI USB model
Trigger Sensitivity = 6 Strain Gage Voltage = 4.9
Gage Factor =2.1 PSI Correction Factor: None
Barrel Temp = 62-64 degrees F measured at the sensor (IR). Rifle Stand: Caldwell Lead Sled
Altitude: 450 ft Chronograph: Chrony Alpha Model
Barrel Type: PacNor .45 Cal Muzzleloader
Breech Plug: Savage Std. (screw-in ventliner) ventliner orifice .031in.
Barrel OD = 1.06 in Barrel ID = .454
Bullet Diam.= .448 Bullet Type = Hornady 250gr. SST. Bullet weight = 250 gr.resized ,unknurled
Sabot: None wads:.462 dia. .03thickx2
Powder:
Trace 1: N110 40 gr. Primer :Fed 209
Trace 2: N110 42 gr. Primer :Fed 209
Shot fm clean barrel, 1 patch Bore Shine, 1 dry patch
Today was a challenge. Dave W. had asked about pressure traces using N110 as a single powder sabotless. Because the powder column was so short, I decided to use a Savage breech plug to better position the powder under the sensor. Also, I thought it best to add another sensor to my barrel closer to the breech plug (.596 in. from BP snout). After getting set up and connected to the new sensor, I fired a test load with a known pressure from previous tests. The first curve checked out fine and I set up to measure a load (N110 40 gr ,250 gr resized SST). Pressures were not consistent and I thought that maybe the new sensor was bad. I switched back to the old sensor and results were no better. At that point I found that one of the tiny female connector pins connecting the shielded cord to the sensor had partially backed out of the plastic connector, giving me an inconsistent connection to the sensor. After pushing the pin back into the plastic connector, I recorded a single trace (N110 40gr 250gr SST) which gave a velocity of 2388 fps and the upper of the two pressure traces shown below. I then ran a second series of one load (N110 42 gr., 250 SST, 3 shots). Somehow, I managed to erase the second series before I was able to transfer it onto my desktop. I had recorded the average peak pressure 41k psi and velocity (2425fps, 3 shots average) before I lost the trace. Back to the drawing board, I re-set up and recorded one more single trace of the 42gr load which is shown as the lower trace below and is consistent with what I saw on the erased pressure traces. What I think I can conclude from this is that 42 gr. of N110 generates velocities which might be useful in a single powder hunting load using a 250 gr. bullet at pressures which are close to max in a PN45 barrel. Interestingly, according to Edge, QuickLoad estimates 5k psi higher pressures for the 42 gr. load than what I measured. Could this difference be due to pressure buildup due to bullet deformation into the lands in a cartridge load? The loads I tested today seemed safe in my gun under the conditions of the tests, but may not be so under other conditions.
Computer: Dell Inspiron Mini Notebook Gage and Module Manufacturer = RSI USB model
Trigger Sensitivity = 6 Strain Gage Voltage = 4.9
Gage Factor =2.1 PSI Correction Factor: None
Barrel Temp = 62-64 degrees F measured at the sensor (IR). Rifle Stand: Caldwell Lead Sled
Altitude: 450 ft Chronograph: Chrony Alpha Model
Barrel Type: PacNor .45 Cal Muzzleloader
Breech Plug: Savage Std. (screw-in ventliner) ventliner orifice .031in.
Barrel OD = 1.06 in Barrel ID = .454
Bullet Diam.= .448 Bullet Type = Hornady 250gr. SST. Bullet weight = 250 gr.resized ,unknurled
Sabot: None wads:.462 dia. .03thickx2
Powder:
Trace 1: N110 40 gr. Primer :Fed 209
Trace 2: N110 42 gr. Primer :Fed 209
Shot fm clean barrel, 1 patch Bore Shine, 1 dry patch
