low or high?

sniperman

hi folks,might be a silly question,but if using low mounts,would the trajectory be flatter from point blank to say 80 yrds,than if using high mounts on a .22LR with subs?

Cass

As a general rule of thumb, and if that is your zero point, then yes. The closer the centre line of the bore is to the centre of the optics the less elevation you usually have to use to get zero. How much depends on the caliber and bullet being used.

So if you mounted a scope with extra high rings on your rifle (say a height of 2.25 inches between centre line of bore and scope) and you used say 25 MOA (100 clicks) to get your zero then usually if you replace the rings with as low as you can go without the scope housing touching the barrel (say a height of 0.5 inches between centre line of bore and scope) you'll find you zero should be less than 25 MOA. (these numbers are examples only)



It's, as said above, all to do with the distance between the centre of the bore and the centre line of the scope. It's why on some ballistic calculators (the good ones) you'll see an option for "Height above Bore".

The idea behind the lowest possible ring height is to get the flattest point for both zero points (near and actual). That sounds a little mad but as all bullets travel in an arc trajectory the bullet actually passes up through your line of sight before coming down again to hit where you are aiming.



The other advantage of having a lower mounted scope is better cheek position and hence better sight picture. If the scope is mounted too high you have to "lift off" the butt stock to get a clear sight picture and this can interfere with your ability to hold and shoot steadily.

sniperman

thanks cass,very helpful as always;)

Wadi14

sniperman, I think I know what ur trying to accomplish with lower scope rings, you asked "would the trajectory be flatter from point blank to say 80 yrds" Now I may be totally wrong in this , lowering or highering the scope will change the line of sight to ur target, closer to the barrel will result in less adjustment of the scope, as line of sight and POA are closer to each other, but am I right in thinking it has no relationship to the trajectory of the round, is the trajectory of a round of similar weight and velocity not pretty constant ?

Cass

Wadi14 wrote: »

but am I right in thinking it has no relationship to the trajectory of the round, is the trajectory of a round of similar weight and velocity not pretty constant ?

None at all.

The bullet will travel the same arc regardless of how high or low the scope is mounted. If you look at the two sets of data i gave above you'll see:

Set one has a -2.2 at the muzzle, 0 at 50 and 6.4 inches at 100. That is 8.6 total adjustment.
Set two has -0.5 at the muzzle, 0 at 50 and 8.1 at 100. Total is still 8.6 of adjustment.