REALLY OVERTHINKING 0 moa / 20 moa rails

[kgarrett]

Work is slow, hunting season is over, some fun out of curiosity,

I've only ever used the standard two piece scope base and ring arrangements, preferably Leupold dual dovetail mounts, on my rifles and a couple of Rugers with their integrated scope rings.

I understand that a 20 moa rail effectively would raise poi roughly 20 inches at 100 yds giving more range via the scope adjustment without holdover at longer ranges. BUT, OVERTHINKING begins…

Since hunters safety education when I was 15, I learned that the trajectory of a bullet crosses the line of sight twice. Once at about 25yds and poi at 100yds. Since the bullet starts to fall immediately after leaving the muzzle there has to be a built in wedge into the rifle for the bullet to "rise" and then "fall" through the line of sight.

So,

a 0 moa picatinny rail is not really parallel to the bore,
I believe the higher the rings are, the more wedge effect is incorporated into the system on any rifle,
a 20 moa picatinny rail is wedge shaped,
a 3-9x40mm in low rings will not have the same ballistics chart trajectory as a 5-25x56mm in super high rings,

I will use the long existing and worldwide used 30-06 shooting a mid weight 165 grain bullet with the popular sized 3-9x40mm scope in medium rings for my questions,

What real affect would putting a 20 moa rail do to the trajectory using a 200yd zero?
Would a 20 moa rail increase maximum point blank range at all?

Thank you

No, it is only useful if you will be shooting long range and need the extra elevation. Whatever distance you zero at will determine your MPBR, the rail cant has no effect as long as your scope has enough elevation adjustment to reach zero.

Some argue that, at least theoretically, your scopes optical performance will be best in the centre of its adjustment range so most of us are better served by 0 MOA rails unless you will be shooting past 5 or 600 yds regularly.

 

[FEENIX]

The only rifle I zero at 100 yds is my 45-70 with 550gr crater bullets. I use a 20moa base to get me out to 300 yds.

Last year, my buddy used his .45-70 to harvest a WT doe. He was using a factory Hornady 325 FTX and zeroed it at 200 yards per the ammo box recommendation. He shot the doe at 100 yards, aiming for the heart, but it was about 5 inches high. As per the box, it is 5.5" high at 100 yards when sighted at 200 yards. It was his first outing with the rifle.

All my lever actions (.30-30, .44 Mag, and .45-70) are sighted at 100 yards.

 

[Turpentine21]

I zero mine at 100

I zero all my LR rifles at 200Y. Yes, Bruce knows his stuff. IIRC, he has a PhD in Optical Engineering. He spent many years in aerospace and defense business before retiring from Teledyne Technologies. He owns High Power Optics in Ventura, CA, but since moved elsewhere but I am not sure where.

I sure don't proclaim to know it all. A goal of mine is to learn something new every day. Stuff like this is exactly what I need.