Pressure Trace:Duplex v. Mixing Again
Aug 26, 2011 13:14:32 GMT -5
Post by TGinPA on Aug 26, 2011 13:14:32 GMT -5
Pressure Trace: Comparison btw Duplex v. Mixing revisited.
On 1/24/2011. I traced a sabotted load comparing duplex layering v. mixing of the powders. Since then several have commented on puzzling inconsistencies in the pressure/velocity data presented at that time. Today, in an attempt to remove any problems in that test which might have been associated with the sabot, I repeated the test using a different sabotless load.
Gage and Module Manufacturer = RSI PTII bluetooth model
Trigger Sensitivity = 4, Strain Gage Voltage =5.096 Gage Factor =2.11 PSI Correction Factor: 4kpsi. Rifle Stand: Caldwell Lead Sled. Altitude: 450 ft Chronograph: Chrony Alpha Model 8 ft from muzzle. (13 fps. added to all recorded velocities to correct for distance of chrony from muzzle.)
Barrel Type: PacNor .45 Cal Muzzleloader Barrel OD = 1.06in. Barrel ID = .452in.
Breech Plug:Savage Std. (screw-in ventliner) ventliner orifice .032 in. Sensor dist fm BP=1.125in. Bullet Diam.= .448in. Type = Hornady XTP .452in. 250gr. resized to .448in Bullet weight = 250gr. ,unknurled. Sabot:None.Wads:.462x.06in lubed fiber under lubed wool. Primer: Fed 209A
Powder:
Trace 1-2 = SR4759(metal can)/H322 14/55gr layered duplex
Trace 3-4 = SR4759(metal can)/H322 14-55gr mixed
Shot fm. dirty barrel. These loads seemed safe in my barrel under the test conditions but may not be so in other conditions.
Of interest are the virtually identical traces for both the mixed and layered loads. Though there was a small velocity difference between the layered and mixed loads (18fps higher with the mixed load), whether that is a significant difference remains to be seen. In retrospect, I think the most reasonable explanation for the results observed in the 1/24 traces is that varying degrees of sabot disruption occurred during the test. For the sabotless load traced today there is no pressure difference between layering and mixing.
TG
On 1/24/2011. I traced a sabotted load comparing duplex layering v. mixing of the powders. Since then several have commented on puzzling inconsistencies in the pressure/velocity data presented at that time. Today, in an attempt to remove any problems in that test which might have been associated with the sabot, I repeated the test using a different sabotless load.
Gage and Module Manufacturer = RSI PTII bluetooth model
Trigger Sensitivity = 4, Strain Gage Voltage =5.096 Gage Factor =2.11 PSI Correction Factor: 4kpsi. Rifle Stand: Caldwell Lead Sled. Altitude: 450 ft Chronograph: Chrony Alpha Model 8 ft from muzzle. (13 fps. added to all recorded velocities to correct for distance of chrony from muzzle.)
Barrel Type: PacNor .45 Cal Muzzleloader Barrel OD = 1.06in. Barrel ID = .452in.
Breech Plug:Savage Std. (screw-in ventliner) ventliner orifice .032 in. Sensor dist fm BP=1.125in. Bullet Diam.= .448in. Type = Hornady XTP .452in. 250gr. resized to .448in Bullet weight = 250gr. ,unknurled. Sabot:None.Wads:.462x.06in lubed fiber under lubed wool. Primer: Fed 209A
Powder:
Trace 1-2 = SR4759(metal can)/H322 14/55gr layered duplex
Trace 3-4 = SR4759(metal can)/H322 14-55gr mixed
Shot fm. dirty barrel. These loads seemed safe in my barrel under the test conditions but may not be so in other conditions.
Of interest are the virtually identical traces for both the mixed and layered loads. Though there was a small velocity difference between the layered and mixed loads (18fps higher with the mixed load), whether that is a significant difference remains to be seen. In retrospect, I think the most reasonable explanation for the results observed in the 1/24 traces is that varying degrees of sabot disruption occurred during the test. For the sabotless load traced today there is no pressure difference between layering and mixing.
TG
They both have nearly identical traces.
