Pressure Trace: PN45 N110v.SR4759m 300xtp
Oct 24, 2011 14:13:41 GMT -5
Post by TGinPA on Oct 24, 2011 14:13:41 GMT -5
Pressure Trace: PN45 N110v.SR4759m 300xtp
I have seen it stated that burn rates of N110, XMP5744 and SR4759 are comparable, with N110 “somewhat” quicker that the other two. Today, I had the opportunity to again gauge what that “somewhat” means. Recently, I heard that N110 (42gr.) had been shot under a 300gr bullet with great consistency and accuracy in a .45 cal barrel. Having previously traced a similar load (43gr) of SR4759 under a 300gr bullet, I thought that the N110 42gr. load under a 300gr bullet would have “somewhat” higher pressures which would still be in what I believe to be a safe peak pressure range and that I could confirm this with a trace. Shown below is the trace of that load compared with a similar load of SR4759 under the same bullet.
In the past, I have always consulted Quickload prior to tracing any powder beyond a range previously traced. Had I bothered to do that, Quickload would have predicted almost exactly what I found.
From this single trace (because I have no intention of repeating it), I learned (and relearned) some stuff: First regardless of accuracy, in a .45 cal barrel, 42gr or more of N110 under a 300gr bullet produces peak pressures which should be approached with significant caution. Second, N110 cannot be freely substituted for SR4759 in any load under any bullet without a very careful workup (a general rule stated clearly in any reloading manual). Third, to avoid surprises, I should do more careful research before moving into uncharted territory.
TG
Gage and Module Manufacturer = RSI PTII Bluetooth model.
Trigger Sensitivity = 7. Strain Gage Voltage =5.096. Gage Factor =2.11. PSI Correction Factor: 4kpsi.(calibrated to my 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. Barrel L.= 23.125in. from front of breechplug.
Breech Plug:Savage Std. (screw-in ventliner) ventliner orifice .032 in. Sensor dist fm BP=1.125in. Bullet Diam.= .452in. Resized to .448in Type= Hornady 300xtp. ,unknurled. Sabot:None. Wads: Lubed wool over .06x.462 fiber wad. Primer: Fed 209A.
Powder: T1= N110 42gr. T2= SR4759(metal can) 43gr.
Shot fm. dirty barrel. These loads seemed safe in my barrel under the test conditions but may not be so in other conditions.
I have seen it stated that burn rates of N110, XMP5744 and SR4759 are comparable, with N110 “somewhat” quicker that the other two. Today, I had the opportunity to again gauge what that “somewhat” means. Recently, I heard that N110 (42gr.) had been shot under a 300gr bullet with great consistency and accuracy in a .45 cal barrel. Having previously traced a similar load (43gr) of SR4759 under a 300gr bullet, I thought that the N110 42gr. load under a 300gr bullet would have “somewhat” higher pressures which would still be in what I believe to be a safe peak pressure range and that I could confirm this with a trace. Shown below is the trace of that load compared with a similar load of SR4759 under the same bullet.
In the past, I have always consulted Quickload prior to tracing any powder beyond a range previously traced. Had I bothered to do that, Quickload would have predicted almost exactly what I found.
From this single trace (because I have no intention of repeating it), I learned (and relearned) some stuff: First regardless of accuracy, in a .45 cal barrel, 42gr or more of N110 under a 300gr bullet produces peak pressures which should be approached with significant caution. Second, N110 cannot be freely substituted for SR4759 in any load under any bullet without a very careful workup (a general rule stated clearly in any reloading manual). Third, to avoid surprises, I should do more careful research before moving into uncharted territory.
TG
Gage and Module Manufacturer = RSI PTII Bluetooth model.
Trigger Sensitivity = 7. Strain Gage Voltage =5.096. Gage Factor =2.11. PSI Correction Factor: 4kpsi.(calibrated to my 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. Barrel L.= 23.125in. from front of breechplug.
Breech Plug:Savage Std. (screw-in ventliner) ventliner orifice .032 in. Sensor dist fm BP=1.125in. Bullet Diam.= .452in. Resized to .448in Type= Hornady 300xtp. ,unknurled. Sabot:None. Wads: Lubed wool over .06x.462 fiber wad. Primer: Fed 209A.
Powder: T1= N110 42gr. T2= SR4759(metal can) 43gr.
Shot fm. dirty barrel. These loads seemed safe in my barrel under the test conditions but may not be so in other conditions.
