Do not feel frustrated. Look at this as a learning situation. I applaud you for your effort.. Most just shoot off a rest & then assume long range hit's in the field are a given. Practice, practice. Not all shots at elk are long range. The vast majority I have taken over the years have been under 200yds .. Have also taken several elk at under & well under 100yds. Practice those off hand shots. Being able to make accurate off hand shots can save a hunt. Be prepared to shoot thru little openings in willow & aspen thickets. Sometimes you will only be able to see the top half or less of an elk's back on the opposite side of a rise. It goes on & on.
