You have to read carefully when they list the cartidge length. One spot, usually at the top page of the cartridge data with other case measurements, they'll give you what the max length of the cartridge should be. That is the longest you can make the cartridge to fit in standard guns in that caliber. Then in the load data they sometimes list c.o.l. measurements for a specific type of bullet and powder. This would be the minimum length you can safely seat that particular bullet and powder combo. You can always go longer, but not shorter.
As far as what length to make them, you can start by measuring a comparable factory round, and start from there. And bullets for revolvers usually have a crimping groove built in, which is where you should seat them to.
As far as the 1.550 length you mention, that is the maximum length for the cartridge you should never go past. It's not the length you should necessarily be loading those bullets to. Past that length, and they may stick out past the front of the chamber, and not allow the cylinder to rotate. If the 135 gr bullet has a crimping groove use that. Or if not, load so the top shoulder of the bullet is just below the case mouth. Then the crimp will roll over the shoulder, and help hold the bullet in place during recoil.
If you can post some pictures of what your reloaded cartridges look like, along with the bullets you are using, that would help a lot. But I still think you are overcrimping the case, or crimping where there isn't a groove or shoulder in the bullet. And this is causing your cases to bulge ever so slight.