As usual, I'm running counter to the prevailing wind here on the fire. You have a fine rifle, in a fine caliber. I say, forget the shooting aids, bags, benches and stuff. Verify your preferred zero at your preferred range, memorize your holdovers if necessary and work on hitting a paper plate from real world positions. Shoot sitting over your knees, learn your limitations in offhand, launch a few prone if you think that's something that can be used in your terrain. At 300 yds in flukey unpredictable winds shooting a 6 inch group is just fine. I'd say forget your range with benches and berms, drive out on the prairie and set up with some targets tacked on cardboard boxes. But start with a verified zero under ideal conditions.
When it comes to doping wind in the field without gadgets, there are some very rough rules that can help. Wind speed, look on youtube, there are videos on wind velocity affecting various grasses, trees, leaves, dirt, and then the wild a__ guess. In any case, if you zero your .270 at 200 say, a full value 10 mph wind will push a 150 gr sbt (about the same length as your 130 copper) roughly 6 inches or about 1/2 of your drop. So memorize your drop. If you want to study this a little, the old Sierra 3rd Ed is a good source. Just pick an old Sierra bullet around the same b.c. as your copper 130... all the dope you need, it's all there on one page. One man's opinion.
Great post.
Another thing I'd add is that JBMballistics.com is your friend. Select your bullet & velocity and play around with different wind scenarios to see what your load will do. Remember, a deer has a roughly 10" diameter vital zone. All you have to do is get a bullet within that.
