Successful long range shooting is about having a "system" and reducing as many variables as possible. It is a two person event. There is too much happening before, during, and after the shot for someone that is not extremely proficient to see and "read" it. With that I am speaking to the far side of 400 yards or so. Inside of that, there is no reason to miss shots that a spotter would help with, although of course everyone misses, yet inside 400 yards this is usually due to a failure to apply the fundamentals of shooting properly.
When talking about things such as Mil vs. MOA everyone needs to be on the same sheet of music. If your idea of long range shooting is to rest you rifle on the rear view mirror and hold "high" there is little point in discussing the finer details as it won't matter. Below is a condensed version of how I explain the entire shooting system to every class/person so that we are speaking the same language. It's too much to write in one piece, and a lot of it is better seen rather than told. Sorry to go on a tangent, but it's hard to understand a single part (mil vs. MOA) without a glimpse of the whole.
Think of your shooting system as the operating system in your computer. Any missed codes and the system fails. Any viruses and the system fails. When I'm speaking of shooting system I mean everything. From your rifle, scope, rest, ballistic program, spotting scope, breathing, NPA, how you zero, how you practice, how you test, trigger control, communication with your spotter, how you make corrections, how you prep for the shot- everything. We should be learning from every round fired and certain gear and techniques will help us with that.
My goal is to make it as foolproof and simple as possible. I want to trim any unnecessary fluff and get rounds accurately on target as quickly as possible. I also want to have a system that is "unmess-withable". That is; even when excited, cold, wet and tired, out of breath, scared, whatever, I will still accomplish the tasks required to hit the target.
It really breaks down into two parts- hardware and software. First with the hardware....
Rifle:
We want a rifle chambered in something that has high BC bullets readily available, and in a cartridge that has low enough recoil to be shot a lot. The style of rifle can be argued forever. The important thing is that the rifle maintains the same relationship to the stock from day to day. This is important obviously for zero retention. So pretty much quality synthetic stocks, bedded and free floated.
Scope:
The most important function of the scope is to maintain zero. Point of aim/point of impact without fail. Next is reliable and consistent adjustments with no dead spots, jumps, or drifts. After that is for the optic to be durable and reliable for extended and repeated use. Last is for it to be clear enough, bright enough and have enough resolution to see the target. Almost all scopes from Leupold VX1's up have adequate glass yet this is the singular topic that people get stuck on because you can show your friends how "bright and clear" the glass is, but you actually have to shoot to see that it does what it's supposed to. Very, very few scopes actually meet the first 3 requirements.
Without getting into a long discussion on BDC versus dialing, etc. Dialing is what you want. More specifically dialing for elevation and holding for wind. It will produce the most hits in the shortest amount of time.
We dial for elevation because the center is always the center- out brains are used to aiming where the crosshairs are. As well it keeps us from holding out in air when we adjust for wind. To do this the scope must adjust correctly 100% of the time.
We hold for wind because it switches too much and too fast to dial. To do this effectively there needs to be reference marks on the reticle. They come in two "types". The most common is a Mil based reticle. Less so MOA based reticles.
The reason for this is quite simple. The American military sniping community got started using MOA as a result of golf shooters using MOA "clicks" on the service rifles. Meanwhile they took Mils from the Artillery side. The result is that American LR shooters were stuck with MOA adjustments and Mil reticles for 30 years. At the same time the world standard for snipers was to use MRAD's, and the europeans were using matching reticles and adjustments nearly from the start. Mil reticles were used heavily for range estimation, and later began to be used for elevation due to scopes not adjusting properly. Around a decade ago the real push came for matching reticles and adjustments, especially the more that shooters were around others using Mil/Mil and for front focal plane optics so that they subtended correctly no matter the power.
The Mil reticles weren't going away in favor of MOA based reticles, it made sense to be talking the same as everyone else, and had just as much to do with the fact that only European scopes were offered in FFP with matched reticles/adjustments and only in Mil. In a nut shell that's how Mil became standard with LR field shooters. And it won't change. While there are no technical disadvantages to using MOA/MOA, options in scopes are extremely limited and options in spotters ridiculously so.
Both are angular measurement, not linear, and in shooting are used exactly the same. Life is simply easier for us to use Mil based scopes. More options, more common, and you will have to learn to use Mils anyway.
For these reasons and the availability of mil reticles in spotters I suggest going Mil.
Next is second focal plane (SFP) versus front focal plane (FFP). If the reticle is designed properly than a FFP is far and away preferable for general use. It's not about "ranging" as most think it is, it's about the reticle being "correct" no matter what. Lots of shots are missed because SFP scopes weren't set on the right power. No matter what you may think, SFP scopes bite everyone eventually. Never worrying about whether the scope is set correctly eliminates a variable. This is really useful when you start getting better and start being able to spot your own shots, as you will need to turn the power down to do it.
SFP versus FFP is kind of like MOA versus Mil. Again, make life easier and go FFP.
Mounting system:
Generally I use picatinny rings and one piece bases as I have seen the least amount of POI wandering with them, however, Tally LW's or DNZ's work well for lightweight rigs. Regardless, degrease them and affix with blue loctite (rust works as well). Torque correctly because lots wonky stuff happens to most scope tubes when rings are over tightened.
Spotting scopes:
Remember that distance shooting is a team event. Trying to learn, or practicing without someone on a spotter and vice versa will take 100x as long to learn. For every shot fired we should be making wind calls and seeing trace and splash for corrections. Make your life easier and get a spotter with a reticle. Actually spotting without a reticle blows in comparison... There are quite a few available with mil based reticles, not so much with MOA.
Get a good tripod.
Software........
