risers

[gnm]

What happens if the front sight riser is 2 mm taller than rear sight riser? Will it run out of elevation adjustment? Any other potential problems?

Anschutz 1913 usually shooting at 50 feet and 25 yards and very occasionally at 50 yards

Risers: 44 mm front, 42 mm rear

Thank you.

[Tim S]

That depends on the rearsight, foresight, and sight radius I expect. But, yes, raising the foresight more than the rearsight will require more elevation adjustment than if the raisers are of equal height*. However, if you have a long extension tube, then a taller front raiser may compensate; some tubes recommend a front raiser/extra raiser.

*A taller rear raiser will compensate for a taller foresight, or just free up elevation. I run approx 12mm under a 22mm tunnel (on a 10in Uptatuner) but 15mm at the back, with a 40in sight radius.

[gnm]

Interesting. Thank you.

I decided not to get this combination and instead buy equal height risers.

[rgibson]

Tim, You are like the James Bond of Smallbore. Living on the ragged edge and pushing the envelope…..;-)

[groverdog1]

using your elevation knob, raise the rear sight by 0.078"

[gnm]

Thank you. I understand this part of math. However, I don't know how much elevation is available on my sights. Also, I am under impression that the taller the risers, the more elevation adjustment is needed due to the increase in the angle between the axis of the barrel and the axis of the now raised sights... Also, I am still not clear how much elevation change is required at different shooting distances because I don't really know the physics and math of ballistics...

In any case, I dropped this idea and acquired a set of risers of identical height.

[Tim S]

The elevation differential is pretty small in my experience. Unless your rearsight is near the top of its elevation travel, it should be fine. When I have added pairs of extra blocks in the past my zero was largely unaffected.

Sight changes for distance used to be very simple: about 6moa between 50 and 100, that's roughly three complete turns of an Anschutz rearsight. Rather than clicking the rearsight, some will use a two-step foresight base: low step for 100 and high for 50 (and closer). Foresight tunnels with an eccentric internal cam like the Womack, Kelly, and today's Nesom do the same thing.

Tall riser blocks can alter the elevation changes though. The bullets' trajectory is the same, but the sightline now intersects it from a different angle. I know of shooters who click UP to go from 50m to 25 yards thanks to a very tall sightline.