Optics Reports Publishing

All Optics: We place the optic in a freezer at 0°F for 30 minutes, then in an oven at 100°F for 30 minutes, and then repeat for a total of two thermal cycles.  We inspect for internal fogging each time the scope is removed from the freezer. We also test mechanical function to make sure that moving parts are not too stiff to operate at cold temperatures.

Rifle Scopes: We test for thermal-induced POA shift by first securing the scope in sturdy V-blocks and precisely aligning the reticle to a distant target. we subject the scope to a thermal cycle test by first aligning the reticle on the V-blocks. We place it in a freezer at 0°F for 30 minutes, then in an oven at 100°F for 30 minutes, and then repeat for a total of two thermal cycles.  We let the scope return to room temperature, place it back on the V-blocks and look for any evidence of the reticle shift. We also inspect for internal fogging whenever the scope is removed from the freezer. Both of these tests can detect POA shifts down to .03 MOA or .01 mrad.

The occurrence of recoil related problems depends a lot on the rifle and caliber. The purpose of our shock testing is not to certify the scope for use with any specific caliber or recoil level, but to induce the scope to shift the POA if such a shift is possible. Some manufacturers test scopes using shock impulse machines, others hit the scope against a “calibrated” surface, while others do nothing at all and let customers perform their recoil testing for them. Optics Reports built a shock testing machine that applies a burst of ~500 G impulses, which is a relatively soft shock. By comparison, the peak acceleration at the scope when firing a typical magnum rifle can be ~5,000 Gs or more.

Rifle scope mounted on Optics Reports shock impulse machine.

We test for shock-induced POA shift by first placing the scope in sturdy V-blocks and precisely aligning the reticle to a distant target. We mount the scope in rings to the shock machine and apply a burst of 10 shock impulses. Then we place the scope back on the V-blocks and look for any evidence of reticle shift. We perform this test once after rotating both turrets in bullet down/left direction, and again after rotating the turrets in the bullet up/right direction. We repeat the entire test three times and report average the POA shift. If a scope is prone to a recoil-induced POA shift, this test will usually detect it.

Comments on “Shooting the Box”: This obligatory live fire test is not performed by Optics Reports.  After reading many optics reviews in which this test was done, we found not a single case in which the reviewer reported that the scope failed this test. It is usually done with insufficient precision to quantify either turret inaccuracy or uncover recoil related turret problems. We regard the “shooting the box” test as a waste of good ammunition, and feel that our time is better spent making good turret accuracy measurements.