Flatted rear aperture.

Simonpie · Post by **Simonpie** » Wed Jan 30, 2013 9:27 pm

When I'm in sitting I get a rear aperture picture that is "D" shaped with the flat part at the bottom. I know not everyone shoots sitting, but it must have come up for others. I've tried moving the comb, thinking my cheek was pushed too far up. I've tried moving the sight forward and aft. It gets a bit better by opening the rear aperture, but doesn't go away entirely. Intentionally opening my eyes very wide helps a bit.
I've seen this on long range guns where the rear sight moves vertically enough that it no longer points directly at the front sight, but in this instance there is no sight adjustment going on from prone or kneeling, where everything is fine.

Anything else I should try?

ShootingSight · Post by **ShootingSight** » Wed Jan 30, 2013 10:43 pm

I have seen this, and bizzarely, if the flat is on the bottom, the blockage is on the top - I don't know why it works that way. Try looking through the sight and take a piece of paper and insert it between the sight and your eye from above. You will see the aperture disappear with the flat spot starting on the bottom. Very strange.

So if you are seeing flat on the bottom, it is likely your eyelid or eyebrow that is crowding from above.

Sounds stupid, but I actually trim my eyebrows for matches. I trim both sides so I don't look lopsided.

mtncwru · Post by **mtncwru** » Thu Jan 31, 2013 12:32 am

ShootingSight wrote:Sounds stupid, but I actually trim my eyebrows for matches. I trim both sides so I don't look lopsided.

If it's stupid and it works, then it's not stupid.

hang · Post by **hang** » Thu Jan 31, 2013 3:17 am

If flat is at bottom it is top eyebrow you are seeing , head is in wrong position you need to get chin further forward so you are not looking out top of eye with top brow getting in way.

Hemmers · Post by **Hemmers** » Thu Jan 31, 2013 4:50 am

ShootingSight wrote: So if you are seeing flat on the bottom, it is likely your eyelid or eyebrow that is crowding from above.

I had this before I got hold of some sight raising blocks. In trying to get my face down to get behind the sights I tilted my head forwards, and ended up looking through my top eyelid, which gave a flat spot on the bottom. If you're shooting sitting then, it probably the same issue.

yana · Post by **yana** » Thu Jan 31, 2013 7:42 am

I have the same I must add but than when shooting standing.
I always felt like I needed a sight riser

robf · Post by **robf** » Thu Jan 31, 2013 12:37 pm

are you using a blind?

Simonpie · Post by **Simonpie** » Thu Jan 31, 2013 2:32 pm

Aha! I just got new glasses. It looks like the upper rim is encroaching. I’ll try to get some sight risers and/or jacking up the nose pieces.
I do frost my left lens. I’ve seen a similar “D” effect if I close my left eye, probably my right lid closing down a bit.
Thanks folks!