Written by Sierra Bullets Ballistic Technician Philip Mahin
Here we are in the next installment of Reloading 101 and last time, I told you I would help get you started on how to use your new equipment so let’s do so.
I’m going to assume you have the press mounted on a solid table top or bench of some kind. I went a little overboard on my bench, but I wanted absolutely no wiggle at all when I used the press, so my bench top is 6” thick and use 6”x6” posts for legs with 2”x6” for bracing. Heavy doesn’t even begin to describe it after it was bolted to the walls surrounding it. It doesn’t move even under extreme stress.
I’m also going to assume you are using a modern ‘O’ style press as that is what I will be describing here. All dies use the same universal thread pattern of 7/8”-14 as do most presses so they all match easily. Because the threads are as coarse as they are, instillation and adjustments are fairly quick so let’s go slow. Almost all instructions on die instillation say to run the ram with a shell holder included all the way to the top, then screw the sizing die down till it touches, then after the ram is lowered a little to create room, screw the die down a quarter to half turn more to create a ‘cam over’ when the ram is fully extended upwards again. Personally, I don’t do this unless the die/chamber combination dictate I need to and you’ll find out why a little later.
If I have a brand new standard full length die (for a bottle neck cartridge) using an expander ball on a de-capping stem, the first thing I’ll do is take the die apart and clean everything. This will get the packing grease out of it and I can inspect everything as I go. What I am inspecting for is the diameter of the expander ball the die offered. Typically, I like to see this at 0.002” to 0.003” smaller than the bullet diameter needed in the cartridge.
This piece is what controls the inner diameter of the case neck as it is pulled out of the die so it makes sure there is enough neck tension on the bullet to hold it in place securely. While the die is still apart, I will begin to set it up for proper use in the press by putting a case that needs to be resized into the shell holder and running the ram all the way to the top. Then I will begin to screw the die down into the press until I feel it touch the case. At that point, the bottom portion of the neck area in the die is resting on the case mouth and any more movement by the die toward the shell holder will result in sizing the case neck down in diameter. This is a good place to refer you to your case lube and make sure you have some on the body of the case. For now, it isn’t needed anywhere else because the expanding stem is still setting on the table.
First, we need to evaluate what type of firearm you are making ammo for before we can continue because the techniques change a little. If you are using a semi-auto firearm, you may need to seat the die all the way down to the shell holder to make sure it sizes the case enough for reliability reasons. That is of course if you are putting the same case back into the same chamber it was fired in. If you are using range pickup brass and putting it into your favorite AR or other semi-auto, your chamber could be smaller than the chamber the brass was fired in to begin with and you may need what is called a small base die (review my last blog post). If you are using a bolt action, the handle offers a lot of camming power so you can use the information above as well as a neck size only die for a while. Of course the neck sizing die only sizes the case neck area so eventually a full length die (or body die) will be necessary for the body.
I want to continue with a bolt action using a full length die so with the ram fully extended upward, the die will size the case just enough to fit it back into the chamber. The course threads can put me past this point quickly so we will use the comparator to set the die up and there is a way to find how much headspace I have before I do any die adjustments. A fired case should fit back into the chamber with a little room to spare but how much room? A few pieces of Christmas present tape (or whatever you happen to have at the time) will stack up on the rear of the case and take up room easily. After I have removed the ejector button from the bolt (if it has one) and I have enough tape on the case to feel the bolt close with a slight resistance, I will record the new number and work from that to make my die adjustments.
As I screw the die body down further and further, I will notice how far I am advancing on the case neck itself if I watch it closely and often. Once the die is in position that it can size almost all of the case neck, this is where I want to use the comparator to measure from the base of the case to the ogive dimension on the shoulder. The caliper needle may not move a lot but it could make a jump higher (indicating longer) as the body of the die starts sizing the body of the case. If the needle does jump, it is because the body was starting to size before the shoulder touched and is causing the shoulder to push upwards. In some situations, this will eliminate any excess headspace and cause the bolt to close heavy or at least snug. Personally, I like a little more room so I will adjust the die body down just enough more to force the shoulder back. The two photos are of a case before firing and the other after and you can see there is only 0.001” between them. This should help keep case stretch down to a minimum and extend the case life a lot.
If I am reloading for several firearms using the same cartridge, this setting may not give me the same result in a different chamber because as we know, factory firearms can vary a lot. Now we come to the removed stem that held the expander ball. Another case to size (with case lube now inside the neck as well as on the outside of the case body) will help me get it set correctly but there are two ways to approach this. If I am using the decapping stem to push the old primer out, there is only one way to set it up. Screw it into the die body enough to make sure the bottom of the decapping stem is slightly below the bottom of the die body. If I am using a dedicated decapping die, I don’t need this decapping stem so I can remove it from the expander ball stem and adjust it so the expander ball is just under the neck area in the die. This is a little easier to do on some die brands than others so don’t worry about it if you can’t make it work. The reason I do this is because the case neck is still engaged into the neck portion of the die as it starts to work over the expander ball. This could help keep concentricity to a minimum so it is worth a try.
One last thing about locking the rings down, do this while there is pressure on the threads. This means lock the body die ring when a case is being forced into it and lock the stem ring when a case is being pulled out. Tune in next time and we’ll set up a straight wall case die set as well as seating dies for both.