In general, we can reference load data for bullet weight that is slightly heavier for the initial powder work up as you can always go higher.
So if you can't find load data for 200 gr bullet, you can reference load data for 225/230 gr bullets.
Not quite.
Published load data is usually developed from chamber pressure testing with single shot universal barrel fixtures (To test multiple calibers) and OAL/COL listed is simply the maximum cartridge length that worked for that barrel.
If you shoot your reloads out of pistols that feed from the magazine, you must determine the cartridge length that will work with your pistol/barrel/magazine:
- First determine the Max OAL for the barrel using the "Plunk Test" - https://www.shootingtimes.com/editorial/reloading-tips-the-plunk-test/99389
- Next, determine the Working OAL by feeding dummy rounds (No powder, no primer) loaded to Max OAL from the magazine without riding the slide. Often Max OAL can be used as Working OAL to reliably feed rounds from the magazine but if they don't, incrementally decrease the OAL by .005" until they do.
- Then using the Working OAL, conduct your initial powder work up. If your Working OAL is longer than published load data for same weight/nose profile bullet, you do not need to adjust the start/max charges. If your Working OAL is shorter than published, consider reducing your start/max charges by .2 to .3 gr.
- For greater accuracy or developing match loads, if the powder charge that produced smallest groups is not at max charge, incrementally decrease the OAL by .005". If shorter OAL produces smaller groups, use shorter OAL.