I want shoot to 1000 yards, how much Internal Adjustment do I need in a riflescope to get there?
This of course depends on caliber, but to use a few examples. A .308 Winchester launched at 2600 FPS will need about 38 to 39 minutes of UP travel to dial up from a 100 yard zero to a 1000 yard zero. This of course will change with barrel length and bullet type. But using a Federal 175 grain match bullet, from a 26 inch barrel, 38 minutes should do it – at least around here at 500 to 800 foot elevation. The same bullet out of an M14/M21 with a 22 inch barrel may need about 42 minutes due to the slower initial velocity. A .300WM from a 26 inch barrel will only need about 31 to 33 minutes. Again, it depends on conditions at the site, but on average, that’ll do.
What this means is that any shooter wanting to scope a rifle for 1000 yards will usually need between 35 and 45 minutes of UP travel available on their rifle scope. So any scope with a TOTAL adjustment range of 60 to 100 minutes is appropriate. You can get away with 55 minutes, but 60 minutes is truly the working minimum. More in this in at the end of this article.
“Only 60 minutes you say?” YES. Consider. That means, mechanically speaking, the scope has 30 minutes of UP travel and 30 minutes of DOWN travel from its mechanical ZERO. 30 minutes will get you to roughly 875 to 900 yards using the above .308 Federal 175 grain match bullet/rifle combo. If you use a 20 minute scope base, which is common practice on most long range tactical rifles today, that 60 minute of angle scope will now allow you to dial all the way out to 50 minutes of UP travel from your 100 yard zero. How? By tilting the scope down 20 minutes of angle, The tapered base allows you to use more internal adjustment solely for UP travel. And 50 minutes of UP will get you out to about 1150 yards with that scope!
So, if your game is true long range shooting, just make sure that when buying a scope that it has between 60 minutes and 100 minutes of angle of internal adjustment and you are golden. You do not actually NEED a 100 M.O.A. capable scope to shoot to 1000 yards. A scope with less internal adjustment, when combined with a modern tapered base, will suffice nicely. One should match the scope/base/CALIBER. For instance, it would be pointless to have a scope with 120 minutes of travel, AND a 20 minute tapered base, on a .308 Winchester rifle. The Maximum Effective Range on the .308 is considered to be approx 800 meters. It has been used effectively out to 1300 meters in combat. Effective range of course, has nothing to do with the ability to hit a target, but everything to do with what happens to the target at that range. So for PAPER or STEEL gong shooting, the max range of the .308 Winchester certainly exceeds its combat effective range. Even if it is running out of steam at 1000 yards, you can still, with skill, shoot a sub-minute group at that range with that caliber. Still, wasting money on a scope with tons of internal adjustment that you will never use, may not be the wisest route to go. In truth, the extra money would be better spent on AMMUNITION. For to practice is to make perfect. We often say there is no $5000 rifle on the planet that will make a poor shooter into a good one. Even if the rifle is capable of quarter M.O.A. groups, it takes a skilled and practiced hand to be able to shoot to that level. The best long range shooters are the ones that actually SHOOT at long range a lot. That takes a lot of ammo.
So to the point, when buying a scope, try to match it well with your final goal. Keep the goal realistic. Keep it smart. The same scope that is perfect for a .338 Lapua Magnum will certainly work well with a .308 Winchester, but if you are actually shooting a .308, you probably do not need to be paying for 125 minutes of internal adjustment when 60 to 75 will be plenty for that caliber. The money saved can be used toward that which you DO need! PRACTICE.
Finally, on the opposite of end of the scale. There are scopes designed for benchrest shooting that have very limited adjustment. Some as little as 26 minutes TOTAL. Even with a tapered base, these scopes are not appropriate for the longe range shooter, regardless of advertising, appearance, or price. Most won’t even allow a 100 yard zero using a tapered base. Generally your zero bottoms out somewhere around 250 yards. So avoid this choice no matter how attractive it seems. Look closely when you see a “varmint” scope. These too often, but not always, have very limited travel. Seems counter-productive, but there you have it. Also, don’t go crazy on objective size. I’ve discussed this in other articles but it bears repeating. Massive scopes are better suited to short range bench competition. Their image often falls apart at long range as soon as you introduce MIRAGE, which is to say EVERY time you go out in anything but winter! So scopes over 25x really need not apply for true long range marksmanship.