Welcome to THR,
lots of great people here.
As mentioned OAL will be determined by bullet type and your firearm.
Some firearms just require shorter OALs than others for the same bullet.
Manuals will list an OAL for example 1.25 with a RN bullet. All RN bullets are not the same shape so your OAL may need to be different than what is listed.
Even with the same bullet your firearm may need a shorter OAL than what is listed.
Remember shorter OALs mean higher pressures.
Do the plunk test to determine the longest OAl you can use, then go a tiny bit shorter to give yourself some wiggle room.
https://www.thehighroad.org/index.p...rel-find-a-max-o-a-l-with-your-bullet.506678/
Start at start charges and work up.
If it takes a while to get someplace to shoot (it does for most of us) you probably want to load a ladder.
For example (Hodgdon data)
230 GR. HDY FMJ FP Hodgdon Universal .451" 1.200" 5.1 716 11,800 CUP 5.6 844 16,800 CUP
So I would load up 10 rounds at 5.1, 20 at 5.3, 20 or so at 5.4 to 5.5
Shoot the lighter ones first of course.
When I do this I like to mark the base of the round with a colored sharpie (Wide tip ones work better, I got a pack from Wallmart with about 8 colors)
So I would mark the 5.1s one color, the 5.3s another etc. Then I make a label with the info for what each color mark means
Example of Label
.45 APC XYZ 230 RN OAL 1.25
11/08/17 Universal Clays
|||||| 5.1 gr
|||||| 5.3gr
||||| 5.5gr
By the way be happy if your sizing dies sizes tight, a good thing IMO.
I don't know what press/powder you are using but be carefull because with a lot of powders it is possible to double charge a .45 case and not have powder spill out.
Needless to say a double charge is a
VERY bad thing. No need to be paranoid, but you do need to be careful.
Since it sounds like you are new to reloading I would just mention to try to avoid distractions while loading.
Another thing to watch for is the Squib load. The one that somehow didn't get any or not enough powder.
A primer alone is enough to drive the bullet into the barrel.
If this happens do not try to shoot it out. Put some oil in the barrel and drive the bullet out with a rod.
So if it doesn't feel right when you shoot it, stop and check and make sure everything is ok.
Light loads are fine as long as they function you pistol and will feel noticeably softer than factory ammo.
Medium to MAX loads will feel closer to factory ammo.
If for some reason recoil seems much higher than factory ammo - stop don't shoot the rest. Pull them apart to be safe.
Buy a bullet puller, and if in doubt take it apart.
If you have a question ask us, no such thing as a dumb question.
Be safe, enjoy!