Last updated on January 25th, 2020 at 10:59 am
Reloading Precision Rifle Ammo on a Progressive Press
Over the course of my 10-years as a competitive rifle shooter, I have lost track of the number of times that the subject of loading ammo has come up in conversation. Whether on the line, in the pits, or around the campfire after dinner, shooters love discussing this subject. Generally-speaking, most would agree that ammo loaded on a progressive press is good enough for pistol shooting, high-volume “blasting” fodder for AR’s, or any application where top-level accuracy is not the primary concern. When top-level accuracy is needed, conventional wisdom leads most hand loaders to a single-stage press. While I agree that most single stage presses are capable of producing excellent match-grade ammo, I don’t agree that they are the only option.
The first press that I ever bought was a Dillon 550B. I purchased it in around 2002 from local reloading guru John Walton at the Gunstop in Minnetonka, MN. At the time, I only owned one rifle, and I had never shot it beyond 50 yards at an indoor range. My reason for getting interested in reloading at the time was to feed my 9mm and .45 ACP pistols, which I was shooting A LOT. I wanted to be able to crank out as much ammo as I could in short order, and John did a good job of demonstrating to me that the 550B was the right tool for the job. Having never loaded a single round of ammo before, and not knowing anyone else who had, the saintly Mr. Walton put up with all of my dumb questions, and prevented me from blowing myself up on more than one occasion. The learning curve on the Dillon was a little steep for a complete greenhorn, but once I started to understand how everything worked, I really began to appreciate the efficiency that was possible with this press.
It would be a few more years before I developed any interest in rifle shooting, and a few more after that before I started to understand some of the differences between “good” and “bad” ammo. I had been loading some basic .223 and .308 rounds on the 550, but nothing very serious, and not in any volume. I finally discovered NRA/CMP highpower in 2007, and that is when my loading needs started to change. In my first season shooting the service rifle, I loaded all of my .223 ammo on the 550 in the exact same way that I would load pistol ammo. Basically, I’d just put a fresh case and bullet on the press, pull the handle, advance the shell holder, and watch a new cartridge fall into the tray. I didn’t have anywhere near enough skill with the rifle to be able to tell if my ammo was good or bad, and all lost points on target were definitely caused by shooter error. After I switched to a match rifle for OTC matches, I started to expect better scores, particularly at the 600-yard line, and started to notice things in my reloading process that could potentially be holding my scores back. I experimented with some single stage presses at this point, but found I couldn’t stand the slow pace of production after my years with the Dillon. I like talking about loading ammo, but I have no love for actually doing it. To me, it’s a necessary evil if I want to keep shooting. I shoot a lot of matches, so I need a lot of ammo to keep rolling, and I decided that a single stage was not going to work for me.
Now, I don’t claim to be an expert at anything, but when I look at a press, it seems to me that the only thing it really does is move things up and down. In my humble observations, it would seem that for my application, the straighter the line that it moves up and down, and the better the parts match up when they get to where they are going, the better my ammo will be. The inherent problem in this department with the Dillon presses is the interchangeable toolhead system. It is designed to be able to quickly change your whole set of dies at once, and it is very good for that task. The down side is that there is a lot of “slop” in the fit of the toolhead to the press. The dies are locked into the toolhead, but the toolhead fits loosely into the slot in the press. I normally have 3 dies in my toolheads when loading rifle ammo; a sizing die in station #1, a powder funnel die in station #2, and a seater in station #3. This means that every time the handle is pulled, 3 different things are happening to 3 different cases at the same time. The case in station 1 is getting sized, #2 is getting a powder charge, and #3 is having a bullet seated, all at once. Tiny variances in neck tension, case length, powder charge, etc, will cause uneven stress to be put on the different stations on the toolhead, and will cause the toolhead to “twist” differently in the press. This can cause your final product to be less straight, or less concentric. Some will argue the importance of having concentric ammo, but I think most would agree that all else being equal, straighter ammo is better.
The way to solve this issue on a Dillon press is to lock the toolhead in place so it doesn’t move. This is really easy, even for a guy like me with next to no mechanical ability. I didn’t come up with any of these ideas, but I use them and have seen measureable improvements in ammo concentricity since setting my press up this way. There are 2 phases to this modification, and 2 parts you will need to make it happen. I believe that you could choose to only do one or the other and still see some benefit, but doing both will yield the best results.
The first item you need is the Floating Die Toolhead from Whidden Gunworks. These toolheads are CNC machined to be flat in the places they need to be flat, and they have a post and special lock rings at stations 1 and 3 to allow you to float your dies.
The toolheads are available here:
Second, is the Uniquetek Toolhead Clamp kit, available here:
The kit consists of a tap & die set to thread the post holes in your press and toolheads, some tiny screws and washers, and even tinier heli-coils to put into the newly threaded holes. If you are handy and know your way around a hardware store, I’m sure you could just buy the stuff in the kit separately and save some money. Once you have used the kit to thread the holes and have installed the heli-coils, you are ready to lock your toolhead down. Presuming that your dies are already correctly set up in the toolhead, you will place an empty case in Station #1(sizer die), and a loaded round in station #3 (seater die). With the ram all the way at the top and both the loaded round and empty case fully engaged in the dies, your toolhead is pushed all the way flat against the top of the slot it rides in. In this position, you will insert the tiny screws into the heli-coils and tighten them to lock the head in place.
With the toolhead locked down, you won’t have any twisting of the toolhead to deal with. The Whidden floating die toolheads allow your sizer and seater to float independently and self align on the cartridge as it enters the die, similar to the way a Forster Coax press operates. For all intents and purposes, it is now like running 3 separate single stage presses simultaneously. Doing this has brought my typical concentricity measurements from .003”-.008” before modifications, to .000”-.003” after, with most rounds falling below .002”. I don’t really even measure runout any more unless I change something in the process, and then only to confirm that everything is still working. I am confident that any ammo I make on this system will have runout below .003”.
I have also done away with the Dillon powder charge system and instead use a generic powder funnel die in its place. I use a separate powder dispenser/scale combo off the press to throw each charge, and then dump them into each case at station #2. At this point, the speed of your powder system will be the limiting factor in how fast you can make ammo. Mine is pretty fast, and the time it takes for each charge to dispense is roughly the same as the time it takes me to do the other tasks. The timing works out well, and I am able to load about 100 rounds per hour with this process. This is the best ammo I can make, and it includes sizing, priming, powder charging, and bullet seating. If I were doing all of the same processes on a single stage, the results wouldn’t be any better, only slower.
These same modifications can also be done on a Dillon 650, and results should be similar. Keep in mind that throwing powder charges off the press will prevent the 650 from running at its full speed potential, and the production rate will be effectively the same as on a 550. Personally, I prefer the 550 for a number of reasons, but both are excellent presses.
If you are a progressive press user wanting to fine-tune your ammo production without sacrificing the speed, these simple modifications might be the ticket for you.
*Originally Published on January 9, 2017