Powder coating increases all the dimensions of a bullet, other than the actual area where the bullet contacts the sizing die. Typically that build out from the substrate is 1.5 to 3 mils, but can be more. To compound the problem, bullet designs vary as well as gun barrel dimensions. The solution to the problem is simple regardless of the caliber or make of firearm. Those that load for accuracy probably already know this, but for those new to the game I will explain.
Overall cartridge length is paramount not only for safety but for accuracy. Back to basics; when a cartridge is chambered it is designed to headspace. Headspace is that distance from a closed bolt to the chamber face. All cases do not headspace the same, some determine the headspace off a rim, a shoulder oron the mouth of the case.
In 9 mm & 45 ACP both are tapered cases designed to headspace on the case mouth. I will focus my comments based on these two calibers as they are the most common. Contrary to what some will tell you, case length definitely makes a difference. When chambered a case that is too long, the excess brass is forced into the bullet and chamber throat, distorting the bullet and a pressure spike when fired, assuming they chamber at all. A short case headspaces on the extractor and not on the mouth and typically results in poorer accuracy.
So the first step in your process is to find several perfect cases to work with. In my experience I have found the best accuracy is obtained in 9 mm with a sized case that measures .750" and for 45 ACP .895" case length. You might have to go through a lot of cases to find these lengths because cartridge manufacturers cut their cases short. After literally measuring thousands of 9 mm cased I have not found a single manufacturer that actually makes a case to (SIAAM) Sporting Arms and Ammunition Manufacturers' Institute specifications. Long cases can be trimmed to the perfect size.
Once you have a few of these cases check the sizing using a chamber gauge to make sure they are sized properly and a "perfect" case to work with. Next step is to take a Dremel rotary tool with a fine cutting dish and make two cuts opposite each other starting at the mouth of the case and going straight down past the spot where your deepest bullet base would reside.
Once you have your case then insert your sized bullet into the mouth of the case just fare enough to hold the bullet without falling out.
Remove the barrel from your handgun and clean the barrel thoroughly. Insert your case with protruding bullet into the barrel and push the case firmly into the chamber using finger pressure. The bullet of sufficient length and design will go into the chamber throat and stop on the rifling lands. Now remove the case from the chamber as gently as possible, a small flat blade screwdriver or other tool may be needed to get it started. Once the case is out measure the overall length of the cartridge. This measurement will give you your maxium overall cartridge length for that particular bullet. Repeat this process several times until you are satisfied you have an accurate OAL. For safety a bullet should be seated back several thousands. Best accuracy is typically found with as little jump as possible. I typically seat my powder coated bullets back about .005". This needs to be done with every bullet and barrel combination. Now set your press dies accordingly; this is where a micrometer seating die pays for itself.
The other issue is powder coated bullet sizing. Realize this when you PC you are making a jacketed bullet. Would you buy .357 jacketed bullets to load in your 9mm, not likely, so why size a PC 9mm bullet several thousands over barrel dimensions. Slug your barrels. In my 30 + 9 mm handguns of various manufactures I have never measured a 9mm barrel that a PC .356" bullet sizing would not properly seal.
If you follow this simple procedure you will eliminate the problem of going to the range with ammo that won't chamber.