Pressure Trace:50cal H4198 70gr 325ftx
Nov 18, 2011 11:19:27 GMT -5
Post by TGinPA on Nov 18, 2011 11:19:27 GMT -5
Pressure Trace:50cal H4198 70gr 325ftx
I attached a gage to a Savage ML II 50cal stainless and traced a few loads. For calibration, RB traces from the tips & hints section of the old board archive were reviewed. For gage calibration, I used a 3 shot average peak pressure (~35kpsi) RB traced for XMP5744 43gr, 250SST (sabotted) and then adjusted the calibration factor in my trace module to give that pressure when that specific load was traced. It is hoped that, this will allow a basis for comparison for others tracing loads in the future. I am not sure of the best way to record barrel ID which is necessary for the pressure calculation. For today, as done in the past, the average distance between lands and grooves (Land D + Groove D)/2 as barrel ID was used.
On another thread, loads for the 325ftx are presently being examined. Because I did not see any traces for this bullet, in RB’s Web-published data, it seemed like a useful place to start. One of Wilmsmeyer’s
“shoulder conditioners” was my starting point. Of interest was the fact that the peak pressure attained with this load in this caliber was below what RB thought of as a maximal load pressure. The fired primer looked OK.
TG
Gage and Module Manufacturer = RSI Bluetooth
Trigger Sensitivity = 7 Strain Gage Voltage =5.096 Gage Factor =2.11 . 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: Savage 50Cal ML II Barrel OD = 1.03 in Barrel ID = .5045
Breech Plug:Savage Std. (screw-in ventliner) ventliner orifice .033 in. Sensor dist fm BP=.587 in. Bullet Diam.= .458in. Bullet Type = 325ftx unknurled. Sabot: HBCR, Wads:none
Powder: H4198 70gr. Primer :Fed 209A
Shot fm dirty barrel. This load seemed safe in my barrel under the test conditions but may not be so in other conditions.
I attached a gage to a Savage ML II 50cal stainless and traced a few loads. For calibration, RB traces from the tips & hints section of the old board archive were reviewed. For gage calibration, I used a 3 shot average peak pressure (~35kpsi) RB traced for XMP5744 43gr, 250SST (sabotted) and then adjusted the calibration factor in my trace module to give that pressure when that specific load was traced. It is hoped that, this will allow a basis for comparison for others tracing loads in the future. I am not sure of the best way to record barrel ID which is necessary for the pressure calculation. For today, as done in the past, the average distance between lands and grooves (Land D + Groove D)/2 as barrel ID was used.
On another thread, loads for the 325ftx are presently being examined. Because I did not see any traces for this bullet, in RB’s Web-published data, it seemed like a useful place to start. One of Wilmsmeyer’s
“shoulder conditioners” was my starting point. Of interest was the fact that the peak pressure attained with this load in this caliber was below what RB thought of as a maximal load pressure. The fired primer looked OK.
TG
Gage and Module Manufacturer = RSI Bluetooth
Trigger Sensitivity = 7 Strain Gage Voltage =5.096 Gage Factor =2.11 . 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: Savage 50Cal ML II Barrel OD = 1.03 in Barrel ID = .5045
Breech Plug:Savage Std. (screw-in ventliner) ventliner orifice .033 in. Sensor dist fm BP=.587 in. Bullet Diam.= .458in. Bullet Type = 325ftx unknurled. Sabot: HBCR, Wads:none
Powder: H4198 70gr. Primer :Fed 209A
Shot fm dirty barrel. This load seemed safe in my barrel under the test conditions but may not be so in other conditions.
