So I've got a new-to-me SDB set up for .45 ACP. I ran a hundred round batch through it yesterday and had several cases not get primed or with high primers. I think what's happening is that the case sometimes slides outwards when it's moving from station 1 to station 2. I found that if I tap the case back into the shellplate at station 2 before I worked the handle, things seemed to work better.

Am I doing something wrong or is this to be expected?

Your shell plate may not be tightened down enough, or you just may need to slow down a bit.

Vince

Not to be expected, when the SDB is properly adjusted, clean and lubed it runs pretty smooth.

You could be having one or more of these things going on.
You might have the wrong locator buttons. 45acp is a #1 button
The shellplate may not be properly adjusted. The bolt that the shell plate rotates on needs to be tight enough to hold the casing down to allow the new primer to seat properly in station 2, but not so tight that it drags on the shell plate.  Be aware there is a set screw that needs to be loosened before adjusting that, and tightened after.  I always put a bit of lube on that shell plate bolt too.

Check those and get back to us.  Yes, they are supposed to be adjusted at the factory for your caliber, but usually a few tweaks are needed.   Try loading only one round at a time till you get the tweaks right.

Dillion has a great help line, give them a call.

While a pain the rear, sorting your brass by headstamp and tuning the shellplate for it will help if you are properly stroking the operating handle.
Rim thickness varies from brand to brand.  Win thinner than say PMC.

Ok, just got back in from the garage. I went to remove and clean/lube the shellplate, and the case pins weren't installed. I guess I was trying to run the press without the pins in? I found them in a baggie and ran 20 rounds through it. Turns out, the SDB works a lot better when all the parts are installed! Who knew?

Priming on the upstroke still feels weird, and I need to reinforce or get some more weight on my bench, but it's working good now.

Thanks!

Glad you got it worked out.  If your bench is not solid you will have more issues.  Might try bolting it to the wall.

Sounds like your new to reloading... Please make sure that all of your 45acp brass is the same size primer!
There are mfg out there that are and have been producing 45acp with small primer pistol primer pockets.
Nothing will ruin your day faster then trying to seat a large pistol primer into a small pistol primer pocket.
YouTube Video

This.  I had a minor stupid issue like you when I got my first SDB. I called Dillon on a Sunday none the less.  They picked up on the second ring and quickly talked me through my issue.  Their tech know their products very well.