I want to put a rail on a Rem Mod 7 so I can have more flexibility in how far away form the eye I can mt. the scope. Since I have never used rails would someone please tell me how I select what I need. What is the significance of 10 MOA, 20 MOA, OR 30 MOA? What does this do and how do I know which I need. What are th pros & cons of Aluminum and steel? Other than a weight difference? Are there ones significantly better than others and how do I tell which are best? Thanks for any and all input.
A rail would certainly allow you more flexibility in positioning your scope for some additional eye relief. The only time you would need a 10, 20 or 30 mOA rail would be if you were going to be dialing long distance and you believe your current or proposed scope will not have enough travel.
Each scope is different as to the amount a elevation travel it will afford you. For example, a Leupold VX-3 4.5-14x40mm CDS with 1" tube has an advertised 71 MOA of maximum travel. Assuming that you were able to zero your rifle at 200 yds and still be somewhere in the middle/center of your scope elevation adjustments (rarely the case!), you would have half, or 35 MOA, of your total elevation travel left to dial up. Now the VX-3 6.5-20X50mm LRT has a 30 mm tube and an advertised 94 MOA total travel. This adds another 23 MOA overall and roughly half, or 12 MOA, in additional elevation adjustments. The Viper Vortex 6.5-20x50mm PA has an advertised total elevation adjustment of 68 MOA. So total elevation travel depends on the make of scope, size of tube and magnification. By putting a scope on a 20 MOA rail, you pick up an additional 20 MOA of total travel in elevation - all of which is usable in dialing up.
So, what does all this mean? Depends on what you are shooting. In my flat shooting 6.5-06 AI, I need 22.25 MOA in order to reach out to 1000 yds. Slower or less aerodynamic bullets will require more. To get out to 1500 yds, I need approx. 49 MOA. of dial up.
So bottom line any decent scope with a standard rail will probably have enough elevation travel to allow you to dial up to 800 - 1000 yds, depending on your caliber. If you want to make sure that you can reach 1000 yds, then get a good scope with at least 60 MOA total travel in elevation. If you want to go beyond 1000 yds, then a MOA rail is probably in order. As a very general rule of thumb, each addl. 10 MOA beyond 1000 yds will buy you another 150-200 yds. in dial up beyond 1000 yds.
Today, nearly all scopes provide you with turets or knobs that have dial up capability. The problem is that a lot of the less expensive scopes do not track well - meaning that they will not hold their zero. This is referred to repeatability. For example, let's say you are zeroed at 200. You dial up 23.5 MOA for a 1000 yd shot. After you make the shot, you dial back down exactly 23.5 MOA. You should have returned to your zero, right? Unfortunately, with a lot of scopes, you will be higher or lower than your zero, because they do not track well - but that is a story for another day.
Any of the high dollar scopes (Premier, Schmidt & Bender, Nightforce, Swarovski and others) seem to track flawlessly. I swore by Leupold for many years, but had trouble lately - others have never had problems. I hear good things about the Burris Black Diamond. Still others seem to indicate that Vortex Vipers track very well and are more economical than Leupold and Burris. In the end, it seems to hold true that you get what you pay for. Do your research, read the forums then place your bet and spin the wheel.
Thanks very much for all the responses. I got a Conquest 4.5 x 14 x 44, EGW Picatinny rail with 0 MOA and Leupy PRW rings this time. I am going to need another scope before the end of the year and will be doing a lot more reading and looking. The Swaro Z5 would be perfect for mounting on a 22-250 AI. The 3.5 to 18 power range and 44 objective are very attractive to me. Even though Swaro, like a number of the high dollar scopes, seems to have an excellent reputation something about the knobs makes me pause ...... they just don't seem very sturdy ... the way they are built or work just seems to raise doubts about their dependability/durability..... they just don't seem to click with authority .... or something. I like the design, compactness, lightness, clarity etc. The 3.5 power on the low end would be excellent for coyote calling and other close in shots. The upper end of 10 to 16 would be excellent for targets, crows, Pdogs etc. The side focus parallax knob is great. The price is AWFUL. A lot of money to spend, especially when there is a nagging doubt there. The big positive with Swaro and Zeiss is their reputation for standing behind their products.
Last edited by Alfred Crouch; 08-10-2010 at 07:44 AM.