A question about A-Frame Site Height vs. Optic Height

AR/M4 AR Technical Discussion
1

Hey everyone,

I’m New to the forum and I have a question. Can anyone tell me the exact dimension from the top of the pic-rail to the tip of the front sight post? I want to mount a scope on a flat top upper that has a standard A-Frame front sight and I need to know how high the center line of the scope has to be to avoid interference with the cross hair vs. sight post view. Also, If i was using a 1-4x power scope I know I would see the sight post at the lowest setting. But, if I’m using a high power optic that starts at say 6.5x, will the sight post affect my view or is the scopes focal plane so far out in front of the sight post that I wouldn’t even see it if it was partially blocking the objective lens? I’m sorry I couldn’t find this dimension, but I’ve been searching and searching and can’t seem to find any downloadable blueprints for an AR. Does anyone know where to find them? :confused:

Thanx. PS - I would measure with a ruler :rolleyes:, but the upper is in the mail, I already have the scope, and need to know what rings to order.

2

At 2x - 4x, the front sight will be visible as a ghostlike shadow in the bottom of your field of view. Through my 4x ACOG, it’s not noticeable unless I’m looking for it. At 5x and above, you won’t be able to see it at all.

Edit: About 1.3" from the top of the rail to the tip of the front sight :slight_smile:

Edit2: Fixed typo. 1.3", not 1.4" :stuck_out_tongue:

3

Thanx, Patriot. That’s kinda what I figured, Although I would like to still try and get the cross-hairs above the sight post. If someone could measure the distance as noted above on their gun and tell me I sure would appreciate it. :wink: