I am building a 375 WSM. Since it is a true wildcat, I have decided to start the build with brass based off the only set of dies I was able to acquire from CH4D.
I began with virgin Nosler 325 WSM brass, which is very thick compared to other Nosler brass I have used.
I am using 21st Century expanding mandrels and their expanding die.
I lubed the inside of the case necks, and initially necked them up to 35 caliber. Then, lubed the inside case necks again and used a 3740 mandrel anticipating 1thou spring back to leave me with 2-3thou neck tension.
The shoulders had obviously moved during the necking up process. So, I annealed the cases, lubed the neck and body and FL sized them (FL sizing was done with the expander ball/decapping pin removed.) with the intention to turn the necks to uniform the brass before I sent the brass off for the chamber reamer.
The problem I have is that the inside neck diameter after FL sizing the cases is 0.362. Which is obviously far too small and will make neck tension too great. Prior to FL sizing the necks are a consistent 0.373.
Outside neck diameter is .393 on FL sized cases and .406 on mandrel only cases.
According to the Nosler and Hornady manuals I have .405 is the outside neck diameter for .375 cartridges.
Neck wall thickness on FL sized case is .017 and .015/0.16 on mandrel only cases.
So, to the guidance a I am requesting;
How do I remedy the brass?
Is it a die problem or should I just find a way to ream the inside of the brass' necks? at the moment I do not own an inside neck reamer. So, if this is the solution a recommendation on a good one would be appreciated. I am using the 21st Century Neck Turning Lathe. If there is an inside neck accessory for it, I am unfamiliar with it.
Can I simply use a .374 expanding mandrel on the sized brass again to get the inside diameter I want, then neck turn or would this move the shoulders again?
All measurements were performed with a Mitutoyo caliper and Mitutoyo ball anvil micrometer.
If you are questioning why I am doing this vs. ordering a reamer that is available, the answer is that I was afraid with it being a wildcat cartridge that components wouldn't match up. I figured if I could start with the brass formed by the tooling I already owned, I could have a tight chamber reamer made to only allow the brass to grow 2-3thou in any direction. This would allow for considerably extended brass life and also make the brass I formed at the bench be ready for the chamber without fire-forming. I could be wrong, but I'm having fun.
This is my first experience neck brass up. So, i apologize if my questions seem rudimentary or nonsensical. If any of the method I am using is flawed, please let me know. Thank you!
I began with virgin Nosler 325 WSM brass, which is very thick compared to other Nosler brass I have used.
I am using 21st Century expanding mandrels and their expanding die.
I lubed the inside of the case necks, and initially necked them up to 35 caliber. Then, lubed the inside case necks again and used a 3740 mandrel anticipating 1thou spring back to leave me with 2-3thou neck tension.
The shoulders had obviously moved during the necking up process. So, I annealed the cases, lubed the neck and body and FL sized them (FL sizing was done with the expander ball/decapping pin removed.) with the intention to turn the necks to uniform the brass before I sent the brass off for the chamber reamer.
The problem I have is that the inside neck diameter after FL sizing the cases is 0.362. Which is obviously far too small and will make neck tension too great. Prior to FL sizing the necks are a consistent 0.373.
Outside neck diameter is .393 on FL sized cases and .406 on mandrel only cases.
According to the Nosler and Hornady manuals I have .405 is the outside neck diameter for .375 cartridges.
Neck wall thickness on FL sized case is .017 and .015/0.16 on mandrel only cases.
So, to the guidance a I am requesting;
How do I remedy the brass?
Is it a die problem or should I just find a way to ream the inside of the brass' necks? at the moment I do not own an inside neck reamer. So, if this is the solution a recommendation on a good one would be appreciated. I am using the 21st Century Neck Turning Lathe. If there is an inside neck accessory for it, I am unfamiliar with it.
Can I simply use a .374 expanding mandrel on the sized brass again to get the inside diameter I want, then neck turn or would this move the shoulders again?
All measurements were performed with a Mitutoyo caliper and Mitutoyo ball anvil micrometer.
If you are questioning why I am doing this vs. ordering a reamer that is available, the answer is that I was afraid with it being a wildcat cartridge that components wouldn't match up. I figured if I could start with the brass formed by the tooling I already owned, I could have a tight chamber reamer made to only allow the brass to grow 2-3thou in any direction. This would allow for considerably extended brass life and also make the brass I formed at the bench be ready for the chamber without fire-forming. I could be wrong, but I'm having fun.
This is my first experience neck brass up. So, i apologize if my questions seem rudimentary or nonsensical. If any of the method I am using is flawed, please let me know. Thank you!
