One thing that nobody mentioned yet in this thread is that when bore-sighting, it is important to get the circles seen while looking through the bore concentric with each other. The one nearer to the eye, on the chamber end of the barrel, should appear to be bigger than the circle on the muzzle end. If these two circles are not concentric when you adjust the scope, your shot will not be where you want it on the paper. This may seem like a little thing, but it is not. The error it induces at 25 yards will be greatly magnified at longer ranges, and even at 100 yards you will spend more ammo getting your scope dialed n. Another thing is that after bore-sighting at 25 yards in this manner, I have found that doing it again at my 100 yard target has often required a few more clicks on the scope turret to get it perfect. Any adjustments that can b made prior to firing the rifle will save ammo.
Another point I'd like to make is this : I always keep a box of inexpensive "bore-fouling" ammo in the range bag, since every rifle I have ever owned has not fired the first round from an oily barrel to the same POI as the fourth or fifth round fired - even when I have run a couple of dry patches down the bore prior to shooting. So, I use this ammo for the first couple shots of 25-yard bore-sighting shots, as well as the first shot at longer range. I make the final adjustment at 100 yards with my pet load with the fancy bullets. Then this load will be shooting where I think it's shooting when I'm shooting at an animal on a hunt.
I recently got one of those laser bore-sighters, since my vision isn't what it used to be - especially up close. I found that doing it at very close range makes a tiny spot on the wall, and this has worked better for me than trying to do it with a bigger spot at 25 yards. The spot is also more distinct when done indoors in less than bright light. Any comments from guys who have a lot of experience with these gadgets would be nice.
. Have fun with your 7mm.
