sighting in a scope

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harm8850	sighting in a scope	Lead	[-]
Posts: 1 (07/15/08 05:23 PM) Reply Quote More My Recent Posts Message Me Connection Blocking Invite Ignore User's Posts Report Post	Tags : None Ihave a smle with a side mounted scope. Before i go to the range, I want to sight in my scope at 25 yards. I am using a laser bore sight. When I go to the range, I want my zero to be at 100 yards. At 25 yards how high or below should the laser hit the target? I am shooting 185 g bullets I just want to get the scope in the area of zero, I can adjust it on the range later. thanks John
hoover		#1	[-]
Posts: 11 (07/17/08 10:08 PM) Reply Quote More My Recent Posts Message Me Connection Blocking Invite Ignore User's Posts Report Post	hi harm....at 25 yds, just have the scope centered on your dot....shoot it and see where youre at.....it shouldnt be too far off from that... i prefer to just look down the bore at a target thats centered as best you can.....then adjust your crosshairs to the center of your target...then your mechanical bore centerline and scope will be at roughly the same point. both methods should work ok!!
reddogge		#2	[-]
Posts: 4728 (07/18/08 12:21 PM) Host Reply Quote More My Recent Posts Message Me Connection Blocking Invite Ignore User's Posts Report Post	I don't have any charts handy to support this but if you zero at 25 you're going to be way high at 100, maybe off the paper. Better to take the bolt out, prop the rifle up and bore sight it at 100 and adjust scope accordingly. Or maybe have it print 1"-1'5" low at 25. See how that does. At 100 yards (which is nothing to a military round) your bullet will be trucking and climbing if zeroed at 25 I would think. "What happened? What the HELL happened?" Jake Holman "The Sandpebbles"
hoover		#3	[-]
Posts: 12 (07/18/08 12:51 PM) Reply Quote More My Recent Posts Message Me Connection Blocking Invite Ignore User's Posts Report Post	yes red, i think you are absolutely correct.... either sight it in a lil low at 25, or just start at 25 and work your way out to 100... sighting a rifle in to me involves using a few different distances to get it dialed....that way you know whether a bullet is climbing or falling at a given distance... i think the key, harm, is to not worry about what the bullet does at 25 compared to 100...get it roughly close at close range, then shoot it at 100 in order to zero it there Last Edited By: hoover 07/18/08 12:53 PM. Edited 1 times.
Parashooter		#4	[-]
Posts: 1500 (07/18/08 02:12 PM) Veteran member Reply Quote More My Recent Posts Message Me Connection Blocking Invite Ignore User's Posts Report Post	OK, looks like we need a lesson in elementary ballistics. Thanks to gravity, the bullet crosses an elevated line-of-sight twice - once at short range (going up) and once at the zero range (coming down). With the usual scope mount, that first crossing happens at about 25 yards for a 100-yard zero. (With low iron sights, it's at about 12 yards.) A trickier problem is the offset. If you boresight at 25 yards with an offset scope, the 100-yard group center will be displaced three times the distance of the offset, in the opposite direction. Boresight offset sights to place the line of sight parallel to the line of bore to avoid this error. Group lateral displacement will be equal to the sight offset at all distances.