RG4570 and Cast Bullets
Posted: 11 Jul 2012 10:14
All you wanted to know about cast bullet performance with the RG45-70. This is the results of 6 months work with my three cast bullet designs. I've included the Beartooth 525-grain Pile Driver but only shot three samples of it; however, I am confident in the performance based on my pressure testing work with my bullets against the calculations in QuickLoad.
I have chosen to reload the RG4570 to a max pressure of 35.0K PSI vs. what I and others load the Marlin 1895 to. The RG4570 is not a 1895 clone but a 336 clone and as such does not have the strength in the receiver at the barrel lugs. I'm very comfortable at this level of performance but it is at my own risk. The actual performance calculations are a Pmax of 40.0K and and Nominal Maximum Pressure (NMP) of 35.0K PSI. Pressure, like velocity, experiences a standard deviation with every shot and what the previous statement indicates is the the average pressure will be 35.0K PSI with the deviations contained inside 40.0K PSI. Your use of this information is at your own risk!
The RG4570 is a very accurate rifle. My work with the Hodgdon powders and all the bullets has proven that powder selection is going to be simply a matter of personal choice. Do your normal load work against a couple of suitable powders and make your own choice for your own rifle.
The above is an example of what I've experienced with the rifle. The three bullets in the target where the Beartooth Pile Drivers at 50-yards (lower right quadrant target). The holes in the cardboard where from my 425-grain bullet in another target that has been removed from the back board.
Whether you shoot these specific bullets or not, the information should allow you to decide which bullet fits your shooting and hunting needs. I've presented the data with graphics below with just about every qualifier you can thing of.
My formatted data, the data I use, is attached as PDF files. Those files are for reference only, your use is at your own risk! All the bullets where sized to .458" and used with a cartridge overall length of 2.500" which provided positive cartridge feed and chambering. The cases were trimmed using the standard, cataloged Lee Precision Case Length Gauge/Trimmer. These trimmers trim the brass slightly under the SAAMI spec, with any cartridge, which worked out very well for matching the case to the crimp groove. Some might ponder the loss of .005" of cartridge OAL, against that used with the Marlin 1895, but it is immaterial with a case of this size. With my load work, I used PMC brass and CCI 200 Large Rifle primers but any 45-70 brass and Large Rifle primer will provide the same performance.
Finally, the RG4570 has met my expectations as a lightweight carbine for hunting. At the bench, my 7 lb rifle can be brutal on the body. The rifle performed so well in every aspect that I sold my Guide Gun. I just received the latest Deer and Deer Hunting magazine and see that they listed the RG4570 in their five rifle "Hot Picks". I understand why, it is a heck of a rifle at a heck of a value.
I have chosen to reload the RG4570 to a max pressure of 35.0K PSI vs. what I and others load the Marlin 1895 to. The RG4570 is not a 1895 clone but a 336 clone and as such does not have the strength in the receiver at the barrel lugs. I'm very comfortable at this level of performance but it is at my own risk. The actual performance calculations are a Pmax of 40.0K and and Nominal Maximum Pressure (NMP) of 35.0K PSI. Pressure, like velocity, experiences a standard deviation with every shot and what the previous statement indicates is the the average pressure will be 35.0K PSI with the deviations contained inside 40.0K PSI. Your use of this information is at your own risk!
The RG4570 is a very accurate rifle. My work with the Hodgdon powders and all the bullets has proven that powder selection is going to be simply a matter of personal choice. Do your normal load work against a couple of suitable powders and make your own choice for your own rifle.
The above is an example of what I've experienced with the rifle. The three bullets in the target where the Beartooth Pile Drivers at 50-yards (lower right quadrant target). The holes in the cardboard where from my 425-grain bullet in another target that has been removed from the back board.
Whether you shoot these specific bullets or not, the information should allow you to decide which bullet fits your shooting and hunting needs. I've presented the data with graphics below with just about every qualifier you can thing of.
My formatted data, the data I use, is attached as PDF files. Those files are for reference only, your use is at your own risk! All the bullets where sized to .458" and used with a cartridge overall length of 2.500" which provided positive cartridge feed and chambering. The cases were trimmed using the standard, cataloged Lee Precision Case Length Gauge/Trimmer. These trimmers trim the brass slightly under the SAAMI spec, with any cartridge, which worked out very well for matching the case to the crimp groove. Some might ponder the loss of .005" of cartridge OAL, against that used with the Marlin 1895, but it is immaterial with a case of this size. With my load work, I used PMC brass and CCI 200 Large Rifle primers but any 45-70 brass and Large Rifle primer will provide the same performance.
Finally, the RG4570 has met my expectations as a lightweight carbine for hunting. At the bench, my 7 lb rifle can be brutal on the body. The rifle performed so well in every aspect that I sold my Guide Gun. I just received the latest Deer and Deer Hunting magazine and see that they listed the RG4570 in their five rifle "Hot Picks". I understand why, it is a heck of a rifle at a heck of a value.
