PN45:5744/RL7 Cold Weather Duplex?
Sept 19, 2011 14:12:37 GMT -5
Post by TGinPA on Sept 19, 2011 14:12:37 GMT -5
Pressure Trace:PN45 5744/RL7 200xtp Cold Weather Duplex?
In 6/2011 I traced a series of duplex loads using RL7 and different boosters under 200gr bullets out of my PacNor 45cal barrel. At that time, though pressures and velocities were in the expected range, secondary pressure spikes were seen. At the time, I thought these due to incomplete powder consumption before the bullet exited from the barrel. After my recent upgrade to the latest Pressure Trace hardware and software from RSI, I have been impressed with the total absence of any sign of secondary spikes in any powder recently tested. Today’s traces continue that trend. To me it suggests that most (if not all) of the secondary spikes recorded in my first 6 months of testing may have been due to artifact, produced either by the hardware or software used during those tests. Comparison between traces before and after my equipment upgrade seems to show that the initial pressure curves and primary peaks are identical. So, maybe all is not wasted. But I am not sure how the areas under the curves or bullet exit times may have been affected.
Though group consistency of this load remains to be seen, because both booster and primary are double based, the load traced today should theoretically resist velocity changes due to cold weather.
**Please note that I posted some of the same information in a previous thread using my old setup:
dougsmessageboards.proboards.com/index.cgi?board=smokeless&action=display&thread=8488
Note that in comparison with the earlier traces, the secondary spike is no longer present.
TG
Gage and Module Manufacturer = RSI PTII bluetooth model
Trigger Sensitivity = 8, Strain Gage Voltage =5.096 Gage Factor =2.11 PSI Correction Factor: 4kpsi.(calibrated to a standard load) 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.= .400in. Type = Hornady XTP Bullet weight = 200gr. ,unknurled. Sabot:Harvester smooth blue Wads: None Primer: Fed 209A
Powder: All Traces SR4759(metal can)/H322 12/54gr
Shot fm. dirty barrel. These loads seemed safe in my barrel under the test conditions but may not be so in other conditions.
In 6/2011 I traced a series of duplex loads using RL7 and different boosters under 200gr bullets out of my PacNor 45cal barrel. At that time, though pressures and velocities were in the expected range, secondary pressure spikes were seen. At the time, I thought these due to incomplete powder consumption before the bullet exited from the barrel. After my recent upgrade to the latest Pressure Trace hardware and software from RSI, I have been impressed with the total absence of any sign of secondary spikes in any powder recently tested. Today’s traces continue that trend. To me it suggests that most (if not all) of the secondary spikes recorded in my first 6 months of testing may have been due to artifact, produced either by the hardware or software used during those tests. Comparison between traces before and after my equipment upgrade seems to show that the initial pressure curves and primary peaks are identical. So, maybe all is not wasted. But I am not sure how the areas under the curves or bullet exit times may have been affected.
Though group consistency of this load remains to be seen, because both booster and primary are double based, the load traced today should theoretically resist velocity changes due to cold weather.
**Please note that I posted some of the same information in a previous thread using my old setup:
dougsmessageboards.proboards.com/index.cgi?board=smokeless&action=display&thread=8488
Note that in comparison with the earlier traces, the secondary spike is no longer present.
TG
Gage and Module Manufacturer = RSI PTII bluetooth model
Trigger Sensitivity = 8, Strain Gage Voltage =5.096 Gage Factor =2.11 PSI Correction Factor: 4kpsi.(calibrated to a standard load) 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.= .400in. Type = Hornady XTP Bullet weight = 200gr. ,unknurled. Sabot:Harvester smooth blue Wads: None Primer: Fed 209A
Powder: All Traces SR4759(metal can)/H322 12/54gr
Shot fm. dirty barrel. These loads seemed safe in my barrel under the test conditions but may not be so in other conditions.