I like the way Sierra refers to the PBR description-- "PBR is calculated for 1/2 the size of the tgt.," i.e if the tgt. is the 12" vital zone, the gun should be sighted in to go no more than 3" above or below the line of sight. This is what i refer to as the CPBR (Conservative PBR).
Steve
Posts: 926 | Location: pueblo.co | Registered: 03 December 2002
45/70 govt---Back in I think 1947 Jack O'Connor wrote an article for Outdoor Life about adjusting a scope. Weaver scopes included a reprint of this article through the time that Weaver scopes were made in El Paso Texas(I think early 80's). The jest of the article was that line of sight is straight and bullet path is an arc. For a vast majority of rifles(Ofcourse it varies)if you set the scope at 25 yards,the line of sight will cut through the arc there and again at a longer distance-----for example with 30-06 it would be about 225 yards. So from muzzle to about 250 or so you could hold dead on. He didnt call this point blank range---but its about the same thing. I do set most of my scopes at 25 and then check them at the longer range--loook for them to be a little high at 100.
Posts: 1289 | Location: San Angelo,Tx | Registered: 22 August 2003
1 of the best writeups i ever saw on the subject was in Bob Hagels' book, "Cartridges and Loads for No. Amer. Game," I think it is. He did an excellent job with it, and described various PBR's for various size tgts./trajectories.
Steve
Posts: 926 | Location: pueblo.co | Registered: 03 December 2002
Chain---how high at 100 would be dependent on all the factors--velocity,weight,etc. The height would have to be charted out. Yes I liked Jack O'Connor and did have a chance to talk to him on the phone. I was an Air Force recruiter at the time(no I wasnt trying to recruit him)and he talked mostly about military. I sure wish I had asked him what his real preference between the .270 and 30-06 was.
Posts: 1289 | Location: San Angelo,Tx | Registered: 22 August 2003
Originally posted by sscoyote: I like the way Sierra refers to the PBR description-- "PBR is calculated for 1/2 the size of the tgt.," i.e if the tgt. is the 12" vital zone, the gun should be sighted in to go no more than 3" above or below the line of sight. This is what i refer to as the CPBR (Conservative PBR).
Steve: One of pet peeves are writers/shooters who think you should sight in such that your bullet is never more than 1/2 of the depth of the vital area (in the example you give, that would be a max of 6 inches high). As I have written numerous times, that only insures a miss 50% of the time at the range in which the bullet is 6 inches high, since half the bullets are going to higher than that (since no rifle shoots one hole groups at 180 yards or so) Worse yet, at the ranges the max traj occurs, game is often aware of you and you don't have time to fiddle fart around.
Back in 80s I hunted a lot with a 400 yard zero - I just put the crosshairs on the brisket of the animal and fired away - as long as the range was 350 yards or less. Works only with a very flat shooting cartridge and I no longer use it.
