.300 WM savage going West

Getting ready for a trip out west this week and did some final tuning on my .300. 1st off that thing will knock your earbuds out and your hat clean off! I got kissed by the scope once yesterday. Lightweight synthetic stock on that gun is not a good idea. After a DMZ one piece Scope base, I put a Nikon Buckmasters 4.5x14x40 on it but never really played with the Bullet drop rings until yesterday. I went to Nikon's "Spot On" interactive compensate program and put in my info. 180 Winchester Power Points were about a 1/2 " group at 80yrds. This is where I needed to zero to get the BDC rings close to 200-300-400 yards etc. Works out to 212,317,406,529 and if you want 635 on the Heavy Duplex. I shot at 200 then 300 and went to check on some gallon jugs and realized this thing works Im just 5" high due to not being dead on the given yardages. So I go back and shoot a 200 and 300 yard shots and put the center of the rings at the lower part of the plastic jugs and BAM! Both were dead center on the up and down and one was 1' off to the left. I was very impressed. Ive never done much long distance shooting because I dont need it where I hunt. I feel confident now that if my buddy gives me the yardage with His range finder I could reach out and touch one. Anybody else use the Nikon BDC and like it?
P.S. If I kill a Mulie next week yall will really have to listen to some bragging.

Better have a good rangfinder to get a read back on a deer at 500. Keep that in mind

You better rezero when you get there for those ranges it won't be the same. Also get the strelok app.

Funny thing is my partner has been to Montana a couple times and he said every deer they took was within 120 yards so all this effort is likely just for fun. However its better to have it and not need it than to need it and not have it.
Question: Why will those ranges not work there? Is it due to elevation and the difference in Air pressures?

Elevation and temp

exactly

Yep. Gun is going to shoot flatter trajectories at higher elevations.

Your nikon app should compensate for elevation and temperature.