BL: Any of the 3.6-18x or 4-16x class powered optics will get you out to 1,000 yards on steel with the proper marksmanship fundamentals, ballistic data, and wind call.
Glass quality, reticle design, and turret repeatability/reliability matter depending on the type of shooting you will be doing.
While you can do it cheaper good glass will allow you to see your target better (image quality = brighter, sharper/greater contrast) and experience less eye fatigue when looking through the rifle scope for extended periods of time.
With a good zero shooting a large frame gas gun consistently takes practice.
“From Frank Galli”
Using a semi automatic large frame rifle as a precision rifle takes a bit more understanding as the rifle will exploit any weaknesses in your fundamentals of marksmanship.
Most guys out there shooting an M4 type rifle are doing so in a dynamic fashion. Usually from a standing or alternate position, moving very dynamic on large close targets. So when these same people move to an AR10 Type rifle in a larger caliber they run into problems with accuracy. We want to look at some fundamental differences in the platform, and how you shoot them accurately.
The AR10 type rifle is heavier, slower, and pushing a bigger bullet with more powder behind it. Depending where the gas key is in relationship to the end of the barrel can matter, as well as how it reacts to the last round in the magazine. These issues are definitely debatable, however the end results speak for themselves. Generally speaking those who ignore the weight difference and the movement in the system fail to use them as a true precision rifle.
For the shooter, the weight and movement in the system is going to exploit any weakness in your fundamentals of marksmanship, especially Trigger Control and Follow Through. If you have a habit of "tapping" your trigger on your bolt gun the gas gun will exploit this dramatically. A great example of this problem is when a shooter experiences the "double tap" with a 308 Gas Gun. They immediately want to blame the trigger or the system but its all shooter. You must follow through completely and allow the recoil pulse to be over before moving on. You don't want to reset the trigger on recoil like with a handgun or carbine in a dynamic situation. You want to delay that reset so we have a distinct and audible click. Trigger reset is key and shows the shooter he is doing it correctly.
Ammunition will matter as well in these systems. Generally speaking they don't like ammunition going over 2650fps for a 175gr 308. The other popular calibers, 6.5mm and 6mm don't have as big an issue because the bullet is moving faster, but in a 308, try to stick with match ammo below 2650. If you are not using Match ammunition, the same you would use in your bolt gun you can't expect bolt gun like results. So be conscious of what you feed your AR10 Type rifle.
It's not your M4 and needs to be treated a bit different. Like the difference between driving an 18 Wheeler Tractor Trailer or a Porsche 911... you drive both the same yet completely different.
