The riflescope offers a single sight alignment via internal reticle with various levels of magnification, thus enabling faster sight-picture acquisition compared to open or "iron sights" under field and match conditions. Because of the single element alignment, a scope is easier to shoot with precision, but not necessarily "more accurate" than a set of aperture or target sights even aextreme ranges which can be as long as 900yds in Palma Competition. Aperture match sights are wonders of precision and repeatability. Once the competitor has his settings established for his ammunition, the rifle almost has a lock on targets chosen at that range. However, the rifles are hardly field worthy due to the complexities of the aperture sight and the tall and relatively delicate ladder-type aperture design front sights.
While the US Army's M-24 sniper rifle system was originally equipped with Redfield International rear and hooded front sight, they were issued for field back-up purposes. Did Army snipers carry them on missions? I dunno, but they no longer issue backup irons to snipers, to my knowledge. IIRC, the M-24 was issued with Leupold & Stevens 10x M3 Ultra sniperscope. More on longrange precision scopes later...
Riflescopes have evolved greatly since the early 1970s. Leupold and Burris remain in the forefront of hunter quality optics. Several new makers have gained marketshare; notably NightForce and Vortex. Weaver and Redfield are old-line names that have seen several reincarnations. Since 2000, the sports of sniping and longrange hunting have grown exponentially in popularity. 1000yd benchrest also grew by many participants as ranges expanded. NightForce began by offering their Benchrest Adj Objective in 8x32 56mm and 10x42 56mm scopes for longrange bench shooters. Their NXS series became the de facto standard for longrange upon introduction around 2004. Sightron is another new firm oriented originally toward bench shooters, but they produce a wide variety of scopes in three different price and features ranges.
Scope mount systems have shown great levels of improvement. More shooters are opting for Picatinny rail specification bases and rings, especially for tactical and longrange shooting applications. Longrange shooting will require
a 20moa (or taller) canted base. Only exception is if your scope has high range of reticle movement like Leupold 4.5-14 Mk 4 which has 100moa elevation. Once zeroed, at least 30moa is minimum to deliver 1000yd capability with a high Ballistic Coefficient bullet. Most scopes, especially older first model Leupolds will have about 45moa total elevation range, thus giving owner maybe 20moa elevation.
Best Advice I can give any really committed shooter is to buy a Bushnell #74-3333 Boresighter-Collimator. The collimating grid allows you to verify scope movement over the 80 x 80 moa grid. Testing at the range is the ultimate proving, but being able to keep records of where a zeroed rifle registers on the grid and prove its movements on the grid enables much versatility (swapping scopes between rifles) and gives advanced diagnosis and setup alignment with minimal effort. If you own a few rifles & scopes, and don't already own a collimator; Get One!
The duplex reticle is most common for hunting and entry level scopes, a great choice for all-around use. The Mil-Dot reticle offers rangefinder functions as well as holdover and holdoff aiming points. Grid-line reticles like Leupold's TMR offer similar functions, but with finer aiming points and range-finding. Wide Duplex, Heavy Duplex, and various German and other specialty reticles like fast response SPR and FC-2 circle-dot/duplex all function for fast-access. Illuminated reticles also enable many minimal light possibilities and possible Bindon Aiming Concept employment with objective lens cap set in place.
With longrange and sniping sports growth, so too have expectations of shooters changed. The optic performance of the longrange/sniping riflescope has improved dramatically. The Schimdt & Bender, Hensoldt, Premier Reticles, U.S. Optics, and NightForce high-power variables have refined quality hugely. Yet, the upper end of this spectrum has a $3500 acquisition cost. To what level of perfection of optical performance does a non-professional shooter require? The "great glass" scopes are commonly very heavy. Scope rings and mount sets typically employed for them are 6 screw top designs or in case of Sako TRG a 3 ring setup. These bring the scope and mount set to or over 3lbs, and often result in a 17lb rifle, perhaps more with ammunition, sling and other attached kit.
My perspective, having owned a NightForce 8-32x 56mm that performed with excellence but was heavy as a boat anchor, is that a scopesight is a sighting system and not a substitute for a spotting scope. None of my precision rifles go over 14pounds, and lighter is better for all-around use. I am not looking for resolution perfection at 1000yds. I want to be able to discern the target and take clear aiming point, but being able to count the thread holes in a small button at great distance is not worth paying another $2500 for. Were I a professional, then maybe.
What I have seen is that even moderate quality gear will perform better than typically credited, if a top-quality mount set is used. Probably the best buy for the money is the Leupold Dual Dovetail mount set. Undeniably, the DD is most durable. For quick release Picatinny style, I've found Warne's vertical split maxima rings to be superb. Leupold horiz split QRW & PRW rings have always marred my scope tubes unless a paper shim is put between them and the tube before removing. For Tactical rings the TPS brand offers best quality for the money. Burris' Zee rings are a fine ring choice but must slide onto the base so clearance could be an issue. Weaver steel bases are a fine choice for low-cost tactical usage. If shimming is necessary, I've bought .05" thick brass sheet stock at hobbystore and made my own. Vary the thickness and measure with your collimator to be sure of your gain. My preference these days, using scopes with 70moa or more elevation is to go with Leupold QR Quick Release system for interchangeability and rugged simplicity. On AR-15 and AR-10 flat tops I like the LaRue 110 QD riser and TPS low rings. Some guys like the LaRue integral QD mount w/rings, but the separate riser allows removal from base and placement on another picatinny rail w/o a ring change and remount.
Leupold VX-II 1.25-4x: Basic scope with mucho elevation movement. Great for heavy recoiling hunting rifles and lever action carbines. Has very short ocular lens w/minimal diameter making this scope an excellent choice for an Armalite A2 carryhandle mount. Extremely durable with long history of proven reliability.
Leupold Mark 4 4.5-14x 50mm with illum TMR reticle. All Leupold 50mm objective models show great improvement in light gathering. Very short oal scope design, unlike so many "great glass" tactical or longrange scopes. Very short and small diameter ocular lens. Superb 100moa elevation and windage enabling this scope to function for longrange w/o a canted scope base. Very lightweight and durable.
Nikon Buckmasters 4-14 and 6-18x 40mm models w/mil-dot reticle and side-focus parallax. Excellent bargains for features and design. Not the most compact scopes, but great performers for the money.
Leupold Mark 4 fixed power scopes: 6x, 10x, and 16x. All excellent and long-proven performers. 6x and 10x were offered in M3 turret configuration which includes military ammunition calibrated elevation cams for .223, .308, .30-06, and .300win mag. Extremely durable, glass etched reticles, relatively compact and lightweight.
In terms of handgun scopes I own a leupold 2x and a Nikon 2.5-8x. Both rugged and handle recoil of the .454Casull well. If you own a .22lr pistol, look into mounting a scope; it'll enable a decent shooting pistol to do all a .22 rifle will out to 50 or 60 yds. Always would prefer to carry a HighPower Rifle and a .22 pistol than vice versa.
As far as open sight, rear aperture type are much faster for sight acquisition and give longer sight radius than a buckhorn or other open type mounted on barrel ahead of receiver. A lever carbine is capable of better precision when a Williams, or other aperture system is installed. The AR-15 A2 integral aperture sight can be adjusted to be on-target out to 600yds with 75/77gr ammunition. Garand and M14 rifles have range-marked sights that are precise with correct ammunition. The ladder sights, flip up & raise bar to 1000+ meters are Area Impact sights which are used in WWI tactic of gang fire where a platoon or company would attempt to drop fire on a distant enemy without expecting aimed hits. To be more clear most surplus rifles so popular now are not longrange propositions unless heavily modified and proven (proof-load fired) to assure modern pressure ammunition will fire safely. Usually, much more cost effective to buy a new commercial sporting rifle than remanufacture one that was made 100yrs ago or longer.
This concludes the Optics Primer. More to come in other articles about using your optics effectively....