I recently set up my Dillon 550 for loading 9x18 Makarov, so I thought I'd give some thoughts on this process for those who are interested in reloading for the Makarov.
About 6 months ago, I found a buyer for my Dillon 450Jr 'B' and decided to upgrade to the Dillon 550. The reasoning, other than wanting a new toy, was that I hated manually putting one primer at a time into the primer cup and I was sick of loading 9x18 Makarov on the single stage press.
The 550 comes set up with the large primer system installed and I needed .45ACP before anything else anyway. I had pretty much loaded my immediate need in .45ACP, so I thought I'd give the caliber change-over a whirl.
The first step was to get on the phone with Dillon and order additional toolheads and additional powder dies (I got the 3 pack, because I want to set up for .45 Colt at some point as well). I highly recommend this over unscrewing the dies since getting your old die adjustments back is a real pain. Besides, the toolheads and powder dies are pretty inexpensive. I did not order additional powder charge and hopper systems, because I don't feel that it's that difficult to move that assembly (two hex screws and a clip and it's off).
I already had the 9mm Para caliber change kit (includes shell holder and case belling attachment that you drop in the powder charge die), so I figured that will work for 9x18M. That is, the shell holders will hold the 9x18M case, and the belling attachment just needs to be screwed down further to bell the 9.2 mm case. Also, I had a set of Hornady 9x18M dies for the single-stage press that I intended to employ on the 550.
Changing the primer system (large pistol to small pistol) is fairly simple. Replacing the primer feed tube requires no tools; unscrew the knurled cap, pull the large pistol tube out, plop the small pistol tube in, replace cap. Then, unscrew the two hex screws under the primer feed system, lift the system, change out the primer transfer bar. You might have to play with the transfer bar travel screw to make sure the primer cup lines up with the hole under stage 1. I recommend keeping the two hex screws loose until you have a good fit for the primer cup.
Setting up the resizing/decapping die was a snap...resize full length without having the die touch the shellplate and you're there. The case belling is a bit more tricky since you have to rotate the powder die while keeping the powder charge system stationary. This is one of the reasons you want to change whole toolheads, not dies, for caliber changes.
The Hornady dies use a combination bullet seat/crimp die. I generally do not like these, particularly at the adjustment stage. Since one often changes bullet types within a caliber, this is the one die that will be readjusted. The general method is to operate the lever and raise the shellplate to its highest position with an empty case in station 3 and screw the die down until it makes contact with the case. Back off the bullet seat screw in the same die. Now, place a bullet onto the case (I typically use an empty case first since with this type of die, I screw a few of them up), operate the lever. Check the bullet depth and adjust the bullet seating screw as necessary. Repeat until it's seated to the right depth. Now, while holding on to the bullet seating screw in order to keep it stationary, rotate the die 1/4 turn and operate the lever. Repeat the last step until you have a decent crimp. It often takes a good amount of fiddling to get this right, in my experience. The Dillon 4 die system is much better for this, IMHO. I found that with the Hornady dies, too much crimp will create a bulge near the case neck that does not look healthy to me.
It might be worthwhile to point out that I use both Starline 9x18M cases and trimmed 9mm Para cases. Both give acceptable results to this point. The 9mm Para cases will probably split sooner since they were made to 9mm proportions, not 9.2 mm. This means the metal is thinner once sized to the larger bore. My bullets are both 95gr Hornady XTP and National Bullet copperwashed 95 gr cast roundnose. 3.5gr of W231 powder has worked well for me with this bullet seated to a case overall length of 25.0 mm in the RN bullet.
General Observations
You can use 9mm Para equipment for just about everything for the 9x18M cartridge. Most dies are tapered such that a few turns of adjustment will work for the larger bore. DO NOT use .356" bullets, untrimmed 9mm Para brass, or .380ACP brass. Accuracy sucks and it's a safety hazard.
Once you've become accustomed to Dillon's 4-die system, you'll be spoiled. I think what I may do in this case is pick up a cheap (e.g. Lee) 9mm Para taper crimp die and screw it down the appropriate depth for 9x18M.
Hornady and Speer are no longer the only manufacturers of the .362" 9x18M bullets. Check National Bullet or Midway.
The Dillon 550 is a very nice press and I recommend it for loading 9x18M. Last time I checked, you can't get 9x18M dies for the Square Deal 'B', but the 9mm Paras might just work with proper adjustment.
I have not yet shot any of the ammo crafted on the Dillon, but my guess is that it will be very similar to the stuff from the Lee Challenger. I suspect that accuracy will be better since I'm not continually swapping and readjusting dies.
If anyone has any other insights into loading the 9x18M, I'd be happy to hear them.