I see posts on gun forums asking what is the maximum range for this rifle...or this caliber...or this scope.
Rifles have no range, bullets have maximum ranges. Typically in multiples of miles or kilometers. But that's not what the person meant when they asked the question, I suppose.
The effective range of equipment is simple to determine. Can a rifle place rounds in 1-1.5 MOA at the maximum expected range that it will be used at,
This is close to correct, only backwards. The maximum effective range is where the rifle/cartridge combination can consistently hit a specified-sized target, and does not include the shooter in any way (too many variables there). I remember the training film in boot camp, "the M-16A1 can consistently hit a man-sized target at 500 meters", which is about 4 MOA (22" shoulder tip to shoulder tip). If your specification is 1.5 MOA, there are a lot of rifles out there that have a maximum effective range of about 100 yds (in spite of the internet claims of sub-moa performance for individual rifles). Typically, a looser specification of 2-3 MOA will give you a good idea of a hunting rifle's maximum effective range. Funny how that number hasn't changed much in the past 50 years
. . .but I digress. We used to laugh at the trite old " as far as you can hit a paper plate, then you're ready", but an 8" plate at 200 yds is about 4 MOA. But since most deer are shot at under 100 yds, it matters little.
If your rifle/ammunition combination can keep all your shots within say 2 MOA, you
could hit a deer-sized target out to 500 yds (whether you are capable of shooting that well or not). But beyond 300 yds, trajectory starts to become an issue, and people miss even though the rifle put the bullet where it was aimed. The shooter can be trained, the rifle shoots how it shoots (which is typically better than many shooters). I have seen shooters with sub-MOA rifles flub 100 yds shots on standing animals, but that's not the rifle's fault.
Scopes do not alter the maximum effective range of the rifle, they are a device to aid the shooter. I shot thousands of rounds of ammo across-the-course with iron sights. Did fairly well, if I say so myself. Nowadays, my vision is nowhere near what it was 40 years ago, so I use a scope.
The rifle doesn't need a scope,
I need a scope.
So, a long-winded way to agree with SP, there is no answer to the question of "what's my rifle's/cartridge's/scope's maximum range?" If it is a modern cartridge with a fair quality barrel and a good scope on it, most shooters could expect to be able to hit a game animal sized target at 200 yds. Beyond that, it gets complicated.