FWIW, there's nuthing a bore sighter can do that your own eyes can't, in most cases......
For bolt rifles, simply benching the rifle properly, removing the bolt and eyeballing through the bore at your target the "carefully" adjusting your scope to point your eyeballing through the bore, easily gets ya on the paper.
The old fellar that taught me this is so good at it, his first round is generally always within 2" of the point he eyeballed and no matter how badly I've done it, first shot is always on the paper.....
Same principle applies to AR15s, simply remove the upper, take out the b/bc/ch and bench the upper.
Sight thru the bore, and like above "carefully" adjust your scope to your eyeballed point....
Re-assemble the upper and fine tune your zero as normal.
The only types of rifles this method won't work on are M1, M1 carbine, M14s, AK, and other military rifles which one cannot take a peak through the bore....
Hope this is some help,
Mike