Len, this should get you the ballpark.
http://www.theweathernetwork.com/weather/cities/indexbc.htm
Just look up a city and it will show the barometric pressure usually from a local airport or environment station.
Not perfect but should be close enough for what we are doing.
Another option are the new generation GPS for mountaineering. They come with a climate mode which will measure pressures. How accurate? No clue. Comparing the two should get you in the right ballpark.
Craig, 200gr of really big bullet leaving at 3000fps is plenty big medicine for even the western kevlar skinned elk at ranges well beyond your comfort zone.
I would not hesitate to shoot one at up to 700 yds with my 6.5-06 and 140gr SST. On a broadside shot, I doubt I would find a bullet.
Your problem will be trying to hit the elk from field rests and naturally windy conditions. You bullet will certainly be lethal enough.
Nikon are very good mechanically but I would still do this torture test.
Go somewhere you can shoot rocks at ranges from 200 to 500yds. Just somewhere safe in the back 40. From the rests you plan on using, set up, range a rock about the size of the kill zone on your elk, dial up, shoot it. One shot one hit - yes or no. Reset scope to 100yd zero. Only take one shot per rock. No sighters at this range.
Let barrel cool, range another, dial up, etc. Keep repeating and you will quickly find how consistent you and your drop table are.
Now increase test by running the elevation knob through its entire range once or twice, then back to zero and dial up. Does it still hit where it is supposed to?
You will be amazed at the number of big dollar scopes that will fail this test. Their owner will claim that they need to dial past then back or only turn the knob slowly or only on Wednesdays after a full moon.
Hoogwash. I want my turrents to go to where I need right now. No mucking about and tweaking. In the field with your trophy deciding to leave the zip code, you need to know that I range, dial up, squeeze and start gutting.
Or else, get a whole bunch closer or get a better scope.
More practise. Stand up and move a round for a bit. Get back into field position, range another target, dial up, etc. Stand up, etc.
Keep repeating it until you gain the confidence to make that cold barrel shot hit. It is harder then it sounds. don't wait for calm days, in fact the worse the weather the better. You need to know what your load is likely to do in those Mountains.
Now increase the task. Go for a brisk walk or jog. Repeat the test and fire in under 10seconds. I think you see where this is going. Always start from your hunting zero on your turrent.
We all test our gear but do we ever test ourselves and that gear. I quickly found that scope eye relief was not right on one rifle, trigger weight not right on another, not field accurate enough for another.
All problems were eventually solved but they did not show up on the range. Test as you are going to hunt. That is the only way to know and for most of us, improve our confidence immensely.
My biggest problem now is finding them but that's another story...
Jerry