7mm-08

[billy]

Planning on using 140 grain core lokt bullets,would a inch high at 50 yards be ok that should put it dead on at 150 to175 yards,any thoughs?

[longwinters]

I think if you are dead on at 50 you will be right on at 150 as the bullet is still rising.

Long

[Graybeard]

I think that to assume ANYTHING about what's going on at 150 yards from a 50 yard shooting session is about as useful as having a yokel behind the counter bore sight it for you.

I've shot them at 25, 50, 75, 100, 150, 200, 250, 300 and at unknown ranges beyond. You just cannot accurately predict anything at longer ranges based on short range shooting. It just plain don't work. Too much room for error. You need to shoot at least 100 yards if you wish to have a clue what it will do at longer ranges. Even then you really MUST shoot at the range you want to know about to be sure.

I suspect an inch high at 100 will do about what you want. That's my usually sight in for the 7-08 for woods hunting.

[huntsman]

It would depend most on your sight height (that is, the distance of the scope's line of sight above the barrel's center of fire) and the velocity of your bullet. Sight height is usually around 1" in modern factory rifles, but can be greater or less depending on scope and mounts. Velocity can only be assumed unless you have a chronograph and can measure it directly out of your own rifle with the ammo in question.

According to published ballistics tables, factory Rem 140 gr corelokt ammo out of a 24" barrel is supposed to run at @ 2,860 fps muzzle velocity, but that could vary greatly from rifle to rifle. Published velocities are also notoriously optimistic and theoretical, so it could be significantly lower in reality. ASSUMING the 2860 velocity and a 1" sight height, the 1" high at 50 yards will THEORETICALLY put you about 2" high at 100, 1.5" high at 150, and dead on at just less than 200 yards. To get your dead-on at 160 yards (150 to 175 as you stated), you would be looking at more like 5/8" high at 50 yards and about 1 1/8" high at 100 yards at this velocity. Lower velocity will of course but more arc in the trajectory and cause the 50 and 100 yard POI to rise, but by less than an inch in any case.

GB is right that you should shoot at 150 yards if you really want to know where the bullet will strike at that distance. There are just too many variables that can change things downrange (bullet spin rate, concentricity of bullet, velocity variation, etc.) Start at 50 to get centered and slightly high (under an inch), move to 100 for your sight-in there, then move to 150 for the sight-in at that distance. Generally if things are working right, my POI doesn't vary more than 1.5" from expected at 150 yards from the 100 yard sight-in in my high-velocity rifles with factory ammo. That's good enough for me in most practical hunting situations. But you have to check to be sure.