Ok I need to replace my front post for my AR and need a little assistance. When shooting the 5 square the current front post is HUGE. think looking at a billboard VS that little square.
What I am after is a 4 moa front post. Do any of you have the calculations done or have a front post that is exactly the same size as the square?
My current is app .100" wide, Bushy AR15 with 20" barrel. Going to order a smaller post but would like to order one and not shot gunn it.
Take the measurement from your eyeball to the front post, in inches, and call that "R".
The width of a 4 MOA front post, in inches, is
R in inches times theta in radians.
Theta, per your spec, is 4 MOA, which is (4/60)° * pi radians/180° = 0.001164 radians,
So (R inches times 0.001164 radians) is the desired width in inches of your proposed 4 MOA front post.
Your front post is gonna appear about 8MOA. A match sight can be gotten at half that size. That should solve your problem.
If you want to be exact, then do the math in the above post.
Your rear aperture diameter is not a factor in the calculation.
http://appleseedinfo.org/smf/index.php?topic=26402.0
I use a 0.062" from WOA it is not 4MOA... :)
http://www.whiteoakarmament.com/xcart/product.php?productid=17707&cat=256&page=4
I just KNEW someone was gonna make me do math :'(
thanks for the help all!
I just got my AR together. My front post is about 8 MOA and I wanted something nice and pointy. A little bit of poking around and I found this: http://www.midwayusa.com/product/427154/kns-front-sight-post-assortment-ar-15-matte-package-of-7 (http://www.midwayusa.com/product/427154/kns-front-sight-post-assortment-ar-15-matte-package-of-7) Ooops! Looks like I got the last one. You can find it elsewhere. I think I measured my 8 MOA post at around .07" wide on a 20" barrel. This set gives you that and some thinner ones to choose from. I haven't put them on yet (stupid job, it cramps my style!) but I'm looking forward to trying the square vs. the round vs. the "V" vs. the inverted "V."
C ya,
brian
Quote from: Aromatic on February 27, 2012, 07:00:13 PM
Your rear aperture diameter is not a factor in the calculation.
http://appleseedinfo.org/smf/index.php?topic=26402.0
I use a 0.062" from WOA it is not 4MOA... :)
http://www.whiteoakarmament.com/xcart/product.php?productid=17707&cat=256&page=4
I run this same front sight post. it's just right imo.
This is what's on mine - http://www.fulton-armory.com/frontsightpostnma2052blade.aspx